Material and methods

Morphological terminology follows McAlpine (Reference McAlpine1981) except that fronto-orbital bristles are divided into superior bristles (ors) and inferior bristles (ori), based on orientation. The ocellar triangle (raised black triangle containing the ocelli) is here referred to as the ocellar tubercle, and the outer pale triangle that often surrounds the ocellar tubercle and extends forwards sometimes as far as the lunule is here referred to as the frontal triangle. The clypeus is ∩-shaped and the thickness refers to its width between outer and inner margins. Characters mentioned in the introduction that are uniform among the Nearctic species will not be repeated for individual species. This study was based on over a thousand specimens housed in the Lyman Entomological Museum, McGill University, Ste-Anne-de-Bellevue, Québec, Canada (LEM); the Canadian National Collection of Insects, Arachnids and Nematodes, Ottawa, Ontario, Canada (CNC); the National Museum of Natural History, Washington, District of Columbia, United States of America (NMNH); the University of Guelph insect collection, Guelph, Ontario (DEBU); the Museum of Zoology, Lund University, Lund, Sweden (MZLU); and the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia (ZISP).

Cerodontha (Icteromyza) atrissima Spencer

(Figs. 1, 13, 21, 25–28)

Figs. 1–4 Heads dorsal view: 1, Cerodontha (Icteromyza) atrissima Spencer; 2, Cerodontha (Icteromyza) capitata (Zetterstedt); 3, Cerodontha (Icteromyza) churchillensis Spencer; 4, Cerodontha (Icteromyza) fuscifrons Spencer. Scale bar = 0.1 mm.

Figs. 5–8 Heads dorsal view: 5, Cerodontha (Icteromyza) griffonensis sp. nov.; 6, Cerodontha (Icteromyza) lineella (Zetterstedt) (inset shows pilosity of eye); 7, Cerodontha (Icteromyza) longipennis (Loew); 8, Cerodontha (Icteromyza) montanoides Spencer. Scale bar = 0.1 mm.

Figs. 9–12 Heads dorsal view (except [11] anterodorsal): 9, Cerodontha (Icteromyza) pilosa Boucher (inset shows pilosity of eye); 10, Cerodontha (Icteromyza) temeculensis Spencer; 11, Cerodontha (Icteromyza) vockerothi sp. nov.; 12, Cerodontha (Icteromyza) woodi sp. nov. Scale bar = 0.1 mm.

Figs. 13–16 Clypeus of 13, Cerodontha (Icteromyza) atrissima Spencer; 14, Cerodontha (Icteromyza) capitata (Zetterstedt); 15, Cerodontha (Icteromyza) churchillensis Spencer; 16, Cerodontha (Icteromyza) griffonensis sp. nov. Scale bar = 0.1 mm.

Figs. 17–20 Clypeus of 17, Cerodontha (Icteromyza) longipennis (Loew); 18, Cerodontha (Icteromyza) montanoides Spencer (inset showing variation); 19, Cerodontha (Icteromyza) vockerothi sp. nov.; 20, Cerodontha (Icteromyza) woodi sp. nov. Scale bar = 0.1 mm.

Figs. 21–24 Heads lateral view: 21, Cerodontha (Icteromyza) atrissima Spencer; 22, Cerodontha (Icteromyza) griffonensis sp. nov.; 23, Cerodontha (Icteromyza) vockerothi sp. nov.; 24, Cerodontha (Icteromyza) woodi sp. nov. Scale bar = 0.1 mm.

Figs. 25–28 Cerodontha (Icteromyza) atrissima Spencer: 25, phallus lateral; 26, phallus ventral view; 27, hypandrium; 28, ejaculatory apodeme. Scale bar = 0.1 mm.

Figs. 29–37 Cerodontha (Icteromyza) capitata (Zetterstedt): 29, phallus lateral, Alaska, 240 mi, Richard Hwy; 30, same in dorsolateral view; 31, phallus lateral, California, Nevada Co.,15 km N. of Truckee; 32, same, in anteroventral view; 33, phallus lateral, Québec, Gaspésie; 34, same, in anteroventral view; 35, phallus, lateral, Newfoundland, St-Johns; 36, same in dorsolateral view; 37, same in anteroventral view. Scale bar = 0.1 mm.

Figs. 38–40 Cerodontha (Icteromyza) capitata (Zetterstedt); 38, hypandrium, California, 13 km N. Truckee; 39, ejaculatory apodeme, California, Sagehen Creek; 40, epandrium, surstylus (above) and cercus (below) in posteroventral view (left side), Québec, Îles de la Madeleine. Scale bar = 0.1 mm.

Figs. 41–47 Cerodontha (Icteromyza) churchillensis Spencer: 41, phallus lateral, Alaska, King Salmon; 42, phallus lateral, Ontario, Luther Marsh; 43, phallus lateral, Québec, Johnville bog and Forest Park; 44, same in ventral view; 45, epandrium in lateral view; 46, hypandrium; 47A, B. ejaculatory apodemes. Scale bar = 0.1 mm.

Figs. 48–51 Cerodontha (Icteromyza) fuscifrons Spencer: 48, phallus lateral; 49, ejaculatory apodeme; 50, hypandrium; 51, epandrium, surstylus (above), and cercus in posteroventral view (left side). Scale bar = 0.1 mm.

Figs. 52–56 Cerodontha (Icteromyza) griffonensis sp. nov.; 52, phallus lateral; 53, phallus ventral; 54, hypandrium; 55, hypandrium lateral; 56, epandrium, surstylus (above) and cercus (left side). Scale bar = 0.1 mm.

Figs. 57–59 Cerodontha (Icteromyza) lineella (Zetterstedt): 57, phallus lateral; 58, hypandrium; 59, ejaculatory apodeme. Scale bar = 0.1 mm.

Figs. 60–66 Cerodontha (Icteromyza) longipennis (Loew): 60, phallus lateral, California, Donner Summit; 61, same except, Ontario, Metcalfe; 62, phallus, distal end; 63A–D, hypandrium, distal half; 64, epandrium and associated structures (surstyli, subepandrial sclerites and cerci) in posteroventral view; 65, epandrium, surstylus and cercus, lateral view; 66, ejaculatory apodeme. Scale bar = 0.1 mm, except Fig. 62 = 0.025 mm.

Figs. 67–70 Cerodontha (Icteromyza) longipennis (Loew) (variations): 67A, phallus lateral, California, Donner Summit; 67B, phallus lateral, typical C. (I.) longipennis, Manitoba, Aweme; 68, phallus lateral, Northwest Territories, Exmouth L.; 69, same except Yukon Territory, Klondike Hwy; 70, same except distal end. Scale bar = 0.1 mm, except Fig. 70 = 0.05 mm.

Figs. 71–75 Cerodontha (Icteromyza) montanoides Spencer: 71, phallus lateral; 72, phallus anteroventral; 73, ejaculatory apodeme; 74, epandrium, surstyli, and subepandrial sclerites, ventral view; 75, epandrium, surstylus, and cercus, lateral view. Scale bar = 0.1 mm.

Figs. 76–77 Cerodontha (Icteromyza) pilosa Boucher: 76, phallus lateral; 77, ejaculatory apodeme. Scale bar = 0.1 mm.

Figs. 78–82 Cerodontha (Icteromyza) temeculensis Spencer: 78, phallus lateral; 79, phalus ventral; 80, ejaculatory apodeme; 81, epandrium (with prominent anal projection), surstylus, and cercus, lateral; 82, hypandrium. Scale bar = 0.1 mm.

Figs. 83–86 Cerodontha (Icteromyza) vockerothi sp. nov.: 83, phallus lateral; 84, phallus ventral; 85, hypandrium; 86, ejaculatory apodeme. Scale bar = 0.1 mm.

Figs. 87–90 Cerodontha (Icteromyza) woodi sp. nov.: 87, phallus lateral; 88, epandrium, surstyli (above), and cerci (below), ventral; 89, ejaculatory apodeme; 90, hypandrium. Scale bar = 0.1 mm.

Cerodontha (Icteromyza) atrissima Spencer, Reference Spencer1977: 244

Specimens examined:MEXICO. Durango: 10 mi. W. El Salto, 9000′, 8.vi.1964, J.F. McAlpine (2 ♂: CNC); same except 21.vi.1964, (2 ♂, 1 ♀: CNC).

Diagnosis. The brown palps, brown frons, completely black clypeus, the long distance between the upper ori and the lower ors, and the male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Frons width 0.30–0.40 mm; ratio of frons width to eye width 1.5–1.9; orbit approximately 0.18–0.21 times the width of frons at level of lower ors; lunule large, semicircular (Fig. 1) or slightly higher; frontal triangle extending anteriorly at most to lower ors; length between ocellar tubercle and margin of lunule 0.16–0.18 mm; base of antennae separated by narrow and slightly elevated keel; clypeus with a medium thickness and with upper margin rounded (Fig. 13); in profile, orbit strongly projecting anterodorsally (Fig. 21) (less so in the female specimen); parafacial absent or moderately projecting, usually not forming a distinct ring (cheek) below eye; two inclinate ori and two reclinate ors; distance between upper ori and lower ors is approximately 1.5–2.0 times the distance between both ori (Fig. 1); gena height at midpoint 0.20–0.22 times the maximum eye height; gena approximately 1.5 times deeper at hind corner than at midpoint; eye bare. Wing length 2.3–2.6 mm in males and 2.9–3.1 mm in females; distance between r-m and dm-cu 1.4–1.6 times the length of vein dm–cu.

Colour: Frons and orbit completely dark brown (Fig. 1); frontal triangle slightly paler than frons; lunule bright yellow (Fig. 1); face and gena usually yellow (antennal foveae sometimes darker and one female specimen with gena brownish near eye margin); antennae brown, except scape yellow; palpus brown; clypeus completely black (Fig. 13). Thorax and abdomen greyish-brown. Legs brown, except all knees narrowly yellow; fore femora yellow for a distance of approximately 0.12–0.15 times the length of femora. Calypter, including margin and fringe dark brown.

Male genitalia. Distal tubules of phallus strongly diverging in ventral view (Fig. 26). Anal projection of epandrium prominent. Cerci small, not extending beyond ventral margin of epandrium in lateral view. Inner margin of epandrium with four to five spines. Hypandrium moderately broad (Fig. 27). Ejaculatory apodeme not greatly expanded, asymmetrical with one side almost straight (Fig. 28).

Geographic distribution: Mexico.

Host plant: Unknown.

Comments: This species is so far known only from the state of Durango in Nearctic Mexico. Three specimens were part of the type series (Spencer Reference Spencer1977). Five additional specimens from the same type locality were examined (see above). Externally this species is very similar to C. montanoides. The colour of the clypeus and the distance between the orbital bristles can usually be used to differentiate both species, but the shape of the distiphallus is most reliable for diagnosis.

Cerodontha (Icteromyza) capitata (Zetterstedt)

(Figs. 2, 14, 29–40)

Agromyza capitata Zetterstedt, Reference Zetterstedt1848: 2750

Agromyza genualis Melander, Reference Melander1913: 261. Syn. Frick Reference Frick1957: 202

Agromyza coloradensis Malloch, Reference Malloch1913: 297. Syn. Frick Reference Frick1957: 202

Dizygomyza capitata, Hendel Reference Hendel1920: 132

Dizygomyza (Icteromyza) capitata, Hendel Reference Hendel1931: 52

Phytobia (Icteromyza) capitata, Frick Reference Frick1959: 386

Cerodontha (Icteromyza) capitata, Nowakowski Reference Nowakowski1967: 654; 1973: 33; Spencer Reference Spencer1969b: 138; 1976: 171; 1981: 167; 1990: 346, 351; Sehgal Reference Sehgal1971: 323; Spencer and Steyskal Reference Spencer and Steyskal1986: 89; Zlobin Reference Zlobin2000: 53

Specimens examined: 743 specimens (CNC, LEM, NMNH, DEBU) from all Canadian provinces and territories, except NT and NU, and from many western states (AK, AZ, CA, CO, ID, MT, ND, NM, NV, OR, UT, WA, WY), and a few eastern states (MI, ME) were examined. Additional material (27 specimens) from Europe was also examined (Appendix 1).

Diagnosis. This species can be recognized by the combination of its black palps, yellow frons, femora that are narrowly yellow at the knees, and the shape of the male genitalia. Other characters such as its larger size and the presence of numerous ori can also be helpful, although variable (see comments).

Description. Frons width 0.35–0.50 mm; ratio of frons width to eye width 1.5–1.9; orbit, each approximately 0.20–0.25 times the width of frons at level of lower ors; lunule large, higher than a semicircle (Fig. 2); frontal triangle hardly differentiated from frons, reaching margin of lunule as a narrow extension (Fig. 2); length between ocellar tubercle and margin of lunule 0.16–0.23 mm; base of antennae separated by narrow and slightly to more strongly elevated keel; clypeus usually thick with upper margin rounded (Fig. 14), rarely thinner, or upper margin more triangular; in profile, orbit strongly projecting anterodorsally; parafacial well developed usually forming a distinct ring (cheek) below eye; usually three (sometimes two, four or five) inclinate ori and two reclinate ors; gena height at midpoint, 0.20–0.30 times the maximum eye height; gena 1.2–1.6 times deeper at hind corner than at midpoint; eye bare. Large species: wing length usually from 2.4–3.0 mm in males (one male specimen with wing length of 2.1 mm), and 2.7–3.7 mm in females (one female with wing length 2.4 mm); distance between r-m and dm-cu 0.8–1.4 times the length of vein dm-cu.

Colour: Frons and lunule bright yellow (Fig. 2). Frons rarely darker (a few female specimens with darker orange or brownish frons, in these cases, lunule and gena are also darker); orbit varying from almost completely yellow (often with only dark spot at base of upper ors) to almost completely black; face yellow; antennae dark brown except scape yellow and sometimes anterior margin of pedicel yellow medially; gena yellow; palpus brown or black; clypeus completely brown (Fig. 14) or narrowly paler centrally. Thorax and abdomen greyish-brown; legs (including coxae) brown, except all knees bright yellow: fore femora yellow for a distance of approximately 0.20 times the length of femora. Calypter yellow, margin and fringe normally dark brown, but sometimes yellowish to pale brown.

Genitalia: Phallus with distiphallus moderately long (see comments), with a smooth curvature bringing the distal part of tubules more or less perpendicular to mesophallus. Distal end of tubules separated from the rest of tubules by a membranous connection, generally short (Fig. 29) but sometimes slightly longer (Fig. 31), in ventral view are normally parallel or slightly diverging but sometimes strongly diverging. Distal end of tubules is somewhat variable (see comments). Anal projection usually prominent but sometimes much reduced. Cerci normal, reaching or almost reaching lower margin of epandrium. Inner margin of epandrium well sclerotized with seven spines, anterior spine slightly larger (Fig. 40). Hypandrium with a constriction a little above midpoint (Fig. 38). Sperm pump with blade well expanded.

Geographic distribution: Widespread in Nearctic and Palaearctic Regions (Zlobin Reference Zlobin2000).

Host plant: Although the records suggest that this species feeds in the stem (Spencer Reference Spencer1969b) or roots (Spencer Reference Spencer1990) of Juncus spp., this is unconfirmed as no larvae or puparia have been found despite extensive searching (Nowakowski Reference Nowakowski1973; Spencer Reference Spencer1990; von Tschirnhaus, Reference von Tschirnhaus1991).

Comments: This is a very common and widespread species, second only to C. (I.) longipennis for number of Nearctic records (Appendix 1). Externally, this species is generally distinguished, among other characters, by its large size and numerous orbital bristles (usually five or more), but a few exceptions exist: for example, a male specimen from Scandia, Alberta, has a wing length of 2.1 mm and only four orbital bristles. Most western Nearctic male specimens have a typical C. (I.) capitata phallus (as illustrated by Spencer Reference Spencer1969b, Reference Spencer1976), best represented here by Figures 29 and 31, with the distal end of tubules small and curved down to an angle of approximately 45–70°. In these specimens the distal tubules measure about 0.20–0.25 mm long (taken vertically from lowest point to highest point, Fig. 29, arrow) and the anterior part of the mesophallus is about 0.12–0.14 mm long. Many eastern Nearctic specimens (e.g., Maine, Iles-de-la-Madeleine, Manitoba, Prince Edward Island, Newfoundland) have the distal end of the tubules slightly bulkier and bent at a 90° angle (Figs. 33, 35), showing some similarities to the illustration provided in Nowakowski (Reference Nowakowski1973: fig. 105). These specimens also have the distal end of tubules more dilated, being most visible in dorsolateral view or ventral view (Fig. 36: width of 0.05 mm, compared with Fig. 30: 0.025 mm in “typical western capitata”), and the tubules are slightly longer with a length of approximately 0.28 mm (Fig. 33, arrow); the anterior part of mesophallus is also longer, measuring normally at least 0.16 mm. Palaearctic specimens of C. (I.) capitata that were examined (see Appendix 1) have the distal tubules matching more closely to Spencer's illustration (“typical western capitata”) than to Nowakowski's. However, these western/eastern differences cannot be applied to all specimens. For example, specimens examined from Ontario, exhibit typical “western phallus” (as illustrated in Figs. 29, 31), and other specimens from various localities exhibit intermediate forms. For this reason, all specimens are here referred to C. (I.) capitata until further evidence is found to suggest that these varied differences are indicative of species-level boundaries.

Although multiple specimens of C. capitata were examined from eastern Canada, records are less frequent towards the south, with specimens examined from only Maine and Massachusetts. Additional eastern localities recorded in previous studies include Illinois (Frick Reference Frick1959), Mississippi and North Carolina (Spencer and Steyskal Reference Spencer and Steyskal1986).

Cerodontha (Icteromyza) churchillensis Spencer

(Figs. 3, 15, 41–47)

Cerodontha (Icteromyza) churchillensis Spencer, Reference Spencer1969b: 138; 1976: 172; 1981: 169; Nowakowski Reference Nowakowski1973: 41; Spencer and Steyskal Reference Spencer and Steyskal1986: 90; Zlobin Reference Zlobin2000: 55

Types examined: Paratypes. CANADA.Manitoba: Fort Churchill, 31.vii.1952, J.G. Chillcott (1 ♂; 1 ♀: CNC); same except 1.viii.1952 (1 ♂; 3 ♀: CNC); 505 mi, Hudson Bay Ry, 16.vii.1952, J.G. Chillcott (1 ♂: CNC). UNITED STATES.Alaska: King Salmon, Naknek R., 1.viii.1952, W.R. Mason (1 ♂: CNC).

Other specimens examined: CANADA.Ontario: Luther Marsh Bog, 27.vi.1985. KN. Barber, sweeps (2 ♂; 2 ♀: DEBU); Wylde Lk. Bog, 8k E. Arthur, 7–13.vii.1987, David Blades (1 ♀: DEBU); Québec: Gatineau Co., Masham Township, 27.vii.1995, E. Ikeda (1 ♀: LEM); Johnville Bog and Forest Park (45°20.7′N, 71°44.5′W), sweeping vegetation, 4.vii.2005, J. Kuchta (2 ♂; 2 ♀: LEM); same except 8.vii.2005 (3 ♂; 2 ♀: LEM); same except 11.vii.2005 (1 ♂; 2 ♀: LEM); same except 13.vii.2005 (1 ♀; 1 ♂: LEM); same except 15.vii.2005 (1 ♂; 3 ♀: LEM); same except 26.vii.2005 (2 ♀: LEM); same except (45°59.8′N, 73°18.0′W), 26.vii.2006, A. Moore (1 ♀; 1 ♂: LEM); Percé, Bridgeville (48°36′N, 64°19′W), sweep vegetation in peat bog, 08.viii.2000, H. Varady-Szabo (3 ♀: LEM). Northwest Territories: Exmouth L. (65°02′N, 115°54′W), 22.viii.1966, G.E. Shewell (3 ♀: CNC); same except 24.viii.1966 (4 ♂; 3 ♀: CNC); same except 25.viii.1966 (1 ♀: CNC). UNITED STATES.Idaho: Priest L., Lookout Mt., 20.viii.1919, A.L. Melander (1 ♀: NMNH). EUROPE.Sweden: Dlr. Floda Sångtorpet Tord Tjeder (1 ♀: MZLU); Hall. Enslöv, 30.vii–4.viii.1957, Fattigkärr, H. Andersson (1 ♂: CNC); Nb. Pajala, Jupukka, 28.vii. starrmyr nr 93. (1 ♀: CNC); Nb. Råneå, Högsön, 10.7.1975, H. Anderson (1 ♀: MZLU).

Diagnosis. The yellow palpus, dark upper frons, bare eyes, narrowly yellow knees, and male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Frons width 0.25–0.35 mm; ratio of frons width to eye width 1.5–2.0; orbit, each approximately 0.20–0.22 times the width of frons at level of lower ors; lunule small (smaller than other Icteromyza species), nearly semicircular or higher; frontal triangle well differentiated from frons, slightly elevated, and apparently extending to margin of lunule as a narrow line; length between ocellar tubercle and margin of lunule 0.14–0.18; base of antennae separated by narrow and sometimes slightly elevated keel; clypeus of medium thickness with upper margin rounded (Fig. 15); orbit slightly projecting anterodorsally; parafacial and cheek absent; normally two inclinate ori (sometimes three) and two reclinate ors; distance between upper ori and lower ors about the same as the distance between both ori; gena narrow: at midpoint 0.14–0.20 times the maximum eye height; gena only slightly deeper at rear; eye bare. Wing length 1.7–2.1 mm in males and 2.2–2.5 mm in females; distance between r-m and dm-cu 1–1.6 times the length of vein dm-cu.

Colour: Frons brown posteriorly, at least at the level of ocellar tubercle (Fig. 3), but sometimes more extensively brown, and yellow (or sometimes orange or yellowish-brown) below; orbit brown posteriorly (to level of anterior or posterior ori, at least narrowly along eye margin) and yellow below; frontal triangle variable, yellowish to darker brown; lunule normally yellow, but sometimes slightly darker if frons darker anteriorly; face, palpus, and gena yellow (face sometimes infuscated with blackish spots); antennae brown except for yellow scape, and pedicel sometimes yellow medially at apex; clypeus completely brown to variably yellow centrally. Thorax and abdomen brown. Legs completely brown with knees yellow: fore femora yellow for about 0.16–0.23 times the length of femora, and sometimes fore coxa narrowly yellowish at apex. Calypter, including margin and fringe, pale brown.

Genitalia: Distiphallus short, S-shaped in lateral view, with weak curvatures (Figs. 41–43). Distal tubules diverging in ventral view with apices converging (Fig. 44). Mesophallus approximately same length as distiphallus, mostly parallel sided. Cerci large and long, extending beyond ventral margin of epandrium (Fig. 45). Inner margin of epandrium with three spines. Anal projection of epandrium prominent. Hypandrium (Fig. 46) narrow, sometimes with a more pronounced constriction above midpoint. Ejaculatory apodeme variable: wide and asymmetrical or narrower and almost symmetrical (Fig. 47A, 47B).

Geographic distribution: Palaearctic region (Zlobin Reference Zlobin2000), Canada (Manitoba, Québec, Northwest Territories), and United States of America (Alaska, Idaho).

Host plant: Unknown.

Comments: In the Nearctic region, this species was previously known only from Alaska and Manitoba. The Californian record (male paratype) listed in Spencer (Reference Spencer1969b, Reference Spencer1981) and Spencer and Steyskal (Reference Spencer and Steyskal1986) represents C. (I.) temeculensis.

Cerodontha (Icteromyza) fuscifrons Spencer

(Figs. 4, 48–51)

Cerodontha (Icteromyza) fuscifrons Spencer, Reference Spencer1969b: 138

Type examined: Paratype. CANADA.Québec: Perkins Mills, 14.viii.1938. G.E. Shewell, 1938 (1 ♀: CNC).

Other specimens examined: CANADA.British Columbia: Revelstoke, 2.vii.1973, H.J. Teskey (1 ♀: CNC). Ontario: 75 km NE Sault Ste.Marie, Witchdoctor Lake, 29.viii.1992, gravel bar in river, T.A. Wheeler (1 ♂: LEM). Québec: Beech Grove, 27.vi.1984, B.M. Bissett (1 ♂: CNC). Saskatchewan: Cypress Hills Prov. Pk., East Block. Grass/sedge on lakeshore. 10.vii.2005. J.R. Vockeroth (1 ♀: LEM).

Diagnosis. This species can be distinguished from other Nearctic Icteromyza by the combination of its hairy eyes, brownish frons (at least above), yellow palpus, and femora narrowly yellow apically.

Description. Frons width 0.25–0.35 mm; ratio of frons width to eye width 1.4–1.8; orbit, each approximately 0.20 times the width of frons at level of lower ors; lunule large, slightly higher than a semicircle (Fig. 4); frontal triangle extending to margin of lunule as a narrow extension; length between ocellar tubercle and margin of lunule 0.15–0.17 mm; base of antennae separated by narrow and slightly elevated keel; clypeus normal, medium thickness with upper margin rounded; orbit with very slight projection anterodorsally; parafacial reduced, sometimes forming narrow ring (cheek) below eye; two inclinate ori and two reclinate ors; distance between upper ori and lower ors shorter than or equal to the distance between both ori; gena at midpoint, 0.18–0.20 times the maximum eye height; gena 1.3–1.5 times deeper at hind corner than at midpoint; eye conspicuously pilose. Wing length approximately 2.3 in males (difficult to measure, wings bent), 2.8 mm in females; distance between r-m and dm-cu 1.4–1.7 times the length of vein dm-cu.

Colour: Frons brown or brownish-orange (Fig. 4), sometimes bright yellow in front; orbit brown for most of its length, yellow anterior to lower ori; frontal triangle yellowish to brown; lunule, face, palpus, and gena yellow (antennal foveae sometimes darker); scape yellow, pedicel brown at base and yellow distally, especially on medial surface (Fig. 4), first flagellomere brown (sometimes narrowly yellow posteriorly on medial surface); clypeus pale, yellowish-brown or dark brown. Thorax and abdomen brown. Legs (including coxae), brown, except all knees yellow: fore femora yellow for about 0.20–0.23 times the length of femora. Calypter yellowish to pale brown, margin and fringe brown.

Genitalia: Distiphallus very long, curving back over mesophallus (Fig. 48). Mesophallus long (0.4 mm in its original bent position) with a distinct sharp curvature near midpoint. Inner margin of epandrium with three spines, including a larger one anteriorly (Fig. 51). Anal projection well developed. Cerci normal, extending slightly beyond ventral margin of epandrium in lateral view. Hypandrium low and broad (Fig. 50). Ejaculatory apodeme with blade slightly expanded (Fig. 49).

Geographic distribution: Canada (British Columbia, Ontario, Québec, and Saskatchewan).

Host plant: Unknown.

Comments: This species was previously known from a single locality in Québec. New localities in British Columbia, Ontario, Québec, and Saskatchewan are here recorded but the species remains rare, with only five specimens known.

Cerodontha (Icteromyza) griffonensis Boucher, sp. nov.

(Figs. 5, 16, 22, 52–56)

Type material. Holotype: ♂. CANADA.Québec: Gaspésie, l'Anse-au-Griffon, nr. Parc Forillon (48°55′N, 64°19′W), sweep. 31.vii.2001, S. Boucher (LEM).

Etymology: The species name is derived from the type locality L'Anse-au-Griffon and also refers to the morphology of the male genitalia that somewhat resembles a gryphon, a mythological creature with an eagle head.

Diagnosis. The combination of its small size (wing length 2.2 mm in male), bare eyes, yellow frons, brown palpus, presence of only two ori, and the shape of the male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Frons width 0.35 mm; ratio of frons width to eye width 1.8; orbit, each approximately 0.24 times the width of frons at level of lower ors; lunule large, in the form of a semicircle (or slightly higher); frontal triangle narrow, and reaching margin of lunule as a narrow extension (Fig. 5); length between ocellar tubercle and margin of lunule 0.16 mm; base of antennae separated by narrow and slightly elevated keel; clypeus narrow (Fig. 16) with upper margin rounded (but brown pigmentation makes it appear triangular); orbit slightly projecting anterodorsally (Fig. 22); parafacial reduced; cheek absent; two inclinate ori and two reclinate ors; gena at midpoint, 0.20 times the maximum eye height; gena 1.4 times deeper at hind corner than at midpoint; eye bare. Wing length 2.2 mm in male; distance between r-m and dm-cu 1.3 times the length of vein dm-cu.

Colour: Frons bright yellow; orbit pale brown above and yellow at level of ori (Fig. 5); frontal triangle same colour as frons; lunule and face yellow; antennae brown except scape and medial tip of pedicel yellow; gena yellow; palpus brown; clypeus mostly brown but narrowly bordered by yellow ventrally (Fig. 16). Thorax and abdomen greyish-brown. Legs brown (including fore and mid-coxae) with all knees yellow: fore femora yellow for a distance of 0.20 times the length of femora. Calypter, including margin and fringe, pale brown.

Genitalia: Distal tubules of phallus short, immediately curving up from mesophallus at an obtuse angle of about 120° (Fig. 52), permitting a full view of phallus in ventral view (Fig. 53). Distal end of distiphallus flaring in lateral view. Distal tubules with a length of approximately 0.18 mm (taken vertically from lowest point to highest point, Fig. 52, arrow). Distal tubules slightly diverging in ventral view (Fig. 53). Inner margin of epandrium with four to six small spines (Fig. 56) (apparently four on one side, but six on opposite side). Hypandrium with a bulbous swelling anteriorly, visible in lateral view (Fig. 55). Cerci short, not reaching ventral margin of epandrium. Ejaculatory apodeme lost.

Geographic distribution: Eastern Canada (Québec).

Host plant: Unknown.

Comments: This new species is externally most similar to C. (I.) capitata and C. (I.) montanoides but can be differentiated from the former by a combination of characters, including its smaller size, number of ori, and male genitalia. The bright yellow frons, the frontal triangle extending to the lunule, and the shape of the clypeus differentiates this species from C. (I.) montanoides. The genitalia of C. montanoides are very similar to the genitalia of C. griffonensis and suggest a close phylogenetic relationship between these species. Cerodontha (I.) griffonensis has slightly shorter distal tubules with an obtuse angle relative to the mesophallus (right angle in C. (I.) montanoides) and the distal ends of the tubules are slightly more flaring. A second visit to the type locality in mid August 2006, failed to collect additional specimens of C. (I.) griffonensis. The species is apparently present earlier in the season.

Cerodontha (Icteromyza) lineella (Zetterstedt)

(Figs. 6, 57–59)

Agromyza lineella Zetterstedt, Reference Zetterstedt1838: 790

Dizygomyza lineella, Hendel Reference Hendel1920: 132

Dizygomyza hirticep, Hendel, Reference Hendel1920: 132. Syn. Rydén Reference Rydén1951: 176

Agromyza pollinosa Melander, Reference Melander1913: 263. Syn. Boucher Reference Boucher2008: 557

Cerodontha (Icteromyza) pollinosa, Frick Reference Frick1957: 202; 1959: 387; Spencer Reference Spencer1969b: 140

Cerodontha (Icteromyza) lineella, Nowakowski Reference Nowakowski1967: 654; 1973: 35; Spencer Reference Spencer1976: 174; Zlobin Reference Zlobin2000: 59; Boucher Reference Boucher2008: 557

Specimens examined:CANADA.Alberta: Sibbald Flats Rec. Area, 08.viii.1980. S. Marshall, Creek (1 ♂: DEBU); Waterton Lakes Nat. Pk., 07–12.vii.1980, H.J. Teskey (1 ♀: CNC). British Columbia: Nancy Greene Park, viii.1980, sweep. S. Marshall (1 ♀: DEBU). Manitoba: Churchill, 25.vi.1930, O. Bryant (1 ♀: NMNH); Farnworth L. nr. Churchill, 22.vii.1952, J.G. Chillcott (1 ♀: CNC); same except 23.vii.1952 (1 ♀: CNC); Fort Churchill, 31.vii.1952, J.G. Chillcott (1 ♀: CNC); same except 4.viii.1952 (4 ♀: CNC); same except 6.viii.1963, J.R. Vockeroth (2 ♀: CNC). Northwest Territories: Aklavik, 25.vii.1931, O. Bryant (1 ♂; 2 ♀: NMNH); Exmouth L., (65°02′N, 115°54′W), 22.viii.1966, G.E. Shewell (4 ♂: CNC); same except 23.viii.1966 (13 ♂; 4 ♀: CNC); same except 24.viii.1966 (30 ♂; 16 ♀: CNC); same except 26.viii.1966 (1 ♂; 1 ♀: CNC); Good Hope, 23.viii.1929, O. Bryant (2 ♂; 1 ♀: NMNH); Hyndman L., (68°15′N, 131°03′W), 1.viii.1969, G.E. Shewell (1 ♂; 5 ♀: CNC). Québec: James Bay Rte, 570.3 km, 53°29′39′′N, 77°37′15′′W, black spruce nr. lake shore, malaise, 9–15 July 2001, M. & B. Buck, debu00182359 (1 ♂: DEBU). Yukon Territory: Klondike Hwy, 15 km S. Carmacks, Bushy Mt. (61°58.2′N, 136°12.2′W), sweep sedges at parking area near river, 25.vii.1998, T.A. Wheeler (1 ♂: LEM); Klondike Hwy, 8.8 km S Twin Lakes, Conglomerate Mt. (61°37.9′N, 135°53.1′W), sweep sedges along Nordenskiold R. 08.vii.1997, T.A. Wheeler (1 ♂; 6 ♀: LEM); same except 15.vii.1998 (2 ♀: LEM); same except 25.vii.1998 (1 ♀: LEM); Klondike Hwy, Emerald Lake (60°15.8′N, 134°45.1′W), sweep veg. at south end of lake, 20.vii.1998, T.A. Wheeler (3 ♀: LEM); Whitehorse, 7.vii.1950, R.H. Robertson (1 ♀: CNC); Whitehorse, Miles Canyon (60°40′N, 135°01.8′W), sweep grass/sedges at Yukon R., 27.vii.1998, T.A. Wheeler (3 ♂; 1 ♀: LEM); Whitehorse, Robert Service C.G. (60°42.1′N, 135°02.7′W), sweep grass and sedges along Yukon R., 11.vii.1998, T.A. Wheeler (1 ♂: LEM); UNITED STATES.Alaska: King Salmon, Naknek R., 11.viii.1952, W.R. Mason (1 ♂: CNC); Sitka, 16.vii.1907, W.T. Shaw (2 ♂: NMNH; previously labelled as cotype and holotype of C. (I.) pollinosa, see Boucher Reference Boucher2008). Wyoming: Yellowstone Park, Yellowstone Lake, 23.vii.1934, A.L. Melander (1 ♀: NMNH). Palaearctic region:ESTONIA: Saaremaa, Viidumäe Nature Reserve, sedge marsh, Nartshuk, 30.vii.1987 (1 ♂: ZISP); SWEDEN: Nb. Pajala, 28.vii. starr, dyig åkant nr 95 (1 ♂: MZLU); Nb. Råneå, Högsön Högsöfjärden, 6.9.1965, H. Anderson (1 ♂: MZLU); Vmld. Ekshärad, 21.vii.1960, W.R.M. Mason (1 ♂: CNC). RUSSIA: Kolskii, Krasnoshchel'ye: shore of Ponoy River, sedge marsh, Gorodkov, 18.viii.1981 (1 ♀: ZISP).

Diagnosis. This species can be recognized from other Nearctic species of Icteromyza by the combination of yellow palps, a yellow frons, strongly projecting orbits, a high gena (0.26–0.33 times the maximum eye height), eyes conspicuously hairy (Fig. 6) and much oblique, femora yellow distally for a distance of about 0.2–0.4 times the length of femora, and the shape of the male genitalia.

Description. This species was redescribed by Boucher (Reference Boucher2008). Additional characters are as follows: clypeus thick with upper margin rounded (similar to capitata, Fig. 14), pale yellowish-brown to dark brown but usually slightly paler centrally. Mid-coxa yellow ventrally for half of its length. Wing length 2.4–3.1 mm in males, and normally 2.8–3.6 mm in females (two female specimens smaller: 2.5 and 2.6 mm).

Genitalia: Distal tubules curving back over mesophallus, normally resting over mesophallus in a position almost parallel to it and reaching at least to midpoint of mesophallus (Fig. 57). Mesophallus long, usually between 0.3 and 0.4 mm and constricted medially. Distal tubules diverging. Cerci long, extending slightly beyond ventral margin of epandrium. Inner margin of epandrium with three to four small spines. Anal projection weakly developed, in the form of a small, wide tubercle. Ejaculatory apodeme narrow, blade only slightly expanding (Fig. 59). Hypandrium large (Fig. 58).

Geographic distribution: Palaearctic region (Zlobin Reference Zlobin2000), Canada (Alberta, British Columbia, Manitoba, Northwest Territories, Québec, and Yukon Territory); United States of America (Alaska, Wyoming).

Host plant. Unknown.

Comments:Cerodontha (I.) lineella was previously known from the Palaearctic region, but was recently recorded in North America (Boucher Reference Boucher2008). Spencer (Reference Spencer1976) used the dark coxae of C. (I.) lineella to differentiate it from Cerodontha (Icteromyza) bohemani (Rydén), but both species are described in a key (Nowakowski Reference Nowakowski1973) as having partially yellow coxae. In the specimens examined for the present study, the colour of the fore coxae of C. (I.) lineella was sometimes completely brown, but more frequently partially yellow apically.

Cerodontha (Icteromyza) longipennis (Loew)

(Figs. 7, 17, 60–70)

Agromyza longipennis Loew, Reference Loew1869: 48

Phytobia (Icteromyza) longipennis, Frick Reference Frick1959: 386

Cerodontha (Icteromyza) longipennis, Spencer Reference Spencer1969b: 140; 1981: 170; 1990: 346, 351; Sehgal Reference Sehgal1971: 324; Spencer and Steyskal Reference Spencer and Steyskal1986: 89

Specimens examined: 449 specimens (CNC, LEM, NMNH, DEBU) from across Canada (except Nunavut) and from most American states (Appendix 2).

Diagnosis. This species can be differentiated from other North American Icteromyza by the bare eyes (at most only scattered short hairs), yellow palpus and frons, dark upper orbits, narrow gena, narrow and pale clypeus, yellow femora for at least 0.35 times of its length (measurement taken on fore femora), and the male genitalia.

Description. Frons width 0.25–0.35 mm; ratio of frons width to eye width 1.4–1.8; orbit, each approximately 0.20–0.24 times the width of frons at level of lower ors; lunule moderately large, higher than a semicircle (Fig. 7); frontal triangle reaching margin of lunule as a narrow extension (sometimes hardly differentiated from frons and difficult to see); length between ocellar tubercle and margin of lunule short: 0.11–0.14 mm; base of antennae approximate; clypeus narrow with upper margin rounded (Fig. 17); in profile, frons only slightly projecting anterodorsally; parafacial and cheek absent; two inclinate ori (a few specimens with only one ori), two reclinate ors; distance between upper ori and lower ors about the same as the distance between both ori; gena narrow, at midpoint 0.13–0.18 times the maximum eye height (rarely 0.20); gena straight or slightly deeper at rear (up to 1.5 times deeper at rear than at midpoint); eye bare or at most with short scattered hairs. Wing length usually (see Variation below) between 1.9 and 2.5 mm in males (rarely up to 2.6 mm), and usually between 2.5 and 2.7 mm in females (rarely up to 2.9 mm; two female specimens smaller: 1.9 and 2.2 mm); distance between r-m and dm-cu 1.2–1.8 times the length of vein dm-cu.

Colour: Frons yellow or orange; orbit brown above, usually as far as upper ors (Fig. 7), but sometimes as far as lower ors, yellow below; frontal triangle same colour as frons; lunule, face, palpus, and gena yellow (antennal foveae sometimes darker); scape yellow, pedicel usually brown basally, yellow apically, first flagellomere mostly yellow (at least medially) in male specimens, and dark brown in females; clypeus yellow to pale yellowish-brown (Fig. 17), sometimes brownish laterally and paler yellow centrally. Thorax and abdomen greyish-brown; legs mostly brown except femora yellow distally for a distance of about 0.35–0.50 times the length of femora (measurement taken on fore femora), fore coxa sometimes yellowish apically and mid-coxa partially yellow. Calypter, margin and fringe usually yellow (rarely yellowish-brown).

Genitalia (see Variation below): Distal tubules long, recurved towards mesophallus, usually reaching close to midpoint of mesophallus (Fig. 60) or more rarely, forming a wider loop and finishing far from mesophallus (Fig. 61). Distal end of distiphallus usually only slightly enlarged and scoop shaped (Fig. 62). Mesophallus long, but usually less than 0.35 mm, narrow and tubular, slightly constricted in the middle. Narrow basal tubular projection of mesophallus (Fig. 67B, arrow) usually approximately 0.25 times the length of mesophallus (sometimes longer, Fig. 67A, see Variation section below). Inner margin of epandrium with approximately four to seven spines (Fig. 64), often in an irregular row (sometimes appearing as two rows). Hypandrium with narrow side arms and with usually one or two apodemes, but sometimes none (Fig. 63A–63D). Anal projection well developed. Cerci longer than ventral margin of epandrium in lateral view (Fig. 65).

Variation 1: The phallus of four male specimens (see Appendix 2: Variation 1) is slightly different, with the distal end of the distiphallus distinctly enlarged (about twice the size of C. longipennis) (Figs. 68–70). These specimens, although somewhat similar to C. longipennis, are all slightly different in external appearance. For example, the BC specimen has a wing length of 2.9 mm and has a larger and darker clypeus. The CA specimen has darker orbit and 5 orbital bristles on both sides; YT specimens (one male and one female) have a darker yellowish-orange frons and finally NT specimen is most identical to C. (I.) longipennis; although the status of these specimens is unclear, they are here tentatively identified as C. (I.) longipennis until further material becomes available for study.

Variation 2: A few western Nearctic specimens (see Appendix 2: Variation 2) externally similar to C. (I.) longipennis, except slightly larger: wing length 2.3–2.8 mm in males and 2.8–3.1 mm in females, had the phallus overall significantly longer (Fig. 67A) than typical C. (I.) longipennis (Fig. 67B). The distal tubules are unusually long, recurved towards mesophallus, almost reaching its base. Mesophallus long and narrow, measuring at least 0.38 mm. Narrow basal tubular projection of mesophallus (Fig. 67A, arrow), 0.33–0.40 times the length of mesophallus.

Geographic distribution: Widespread Nearctic.

Host plant: Reared from Juncus xiphioides E. Mey. in California (Frick Reference Frick1959; Spencer Reference Spencer1981).

Comments:Cerodontha (I.) longipennis is very common and the most widespread Nearctic species of Icteromyza, occurring in almost all Canadian provinces and American states (Appendix 2). Cerodontha (I.) longipennis is externally similar to the Palearctic species C. (I.) bohemani. Cerodontha (I.) bohemani has a wing length of 2.5–3.0 mm (Nowakowski Reference Nowakowski1973; Spencer Reference Spencer1976) and a phallus characterized by a slightly enlarged and strongly chitinized distal end of tubules as illustrated in Spencer (Reference Spencer1969a) (lectotype). Spencer (Reference Spencer1976) and Nowakowski (Reference Nowakowski1973) also illustrated the phallus of C. (I.) bohemani but with different distal end (not as enlarged nor chitinized), similar to the distal end found in C. (I.) longipennis. One specimen of C. (I.) bohemani from Sweden (Sk. Kullaberg, 9.8.1969, H. Andersson, 1 ♂: MZLU) was examined and the distal end of the tubules is slightly enlarged and conspicuously chitinized, as illustrated for the lectotype (Spencer Reference Spencer1969a), the mesophallus is long (0.4 mm), and the narrow basal tubular projection is 0.27 times the length of the mesophallus. Cerodontha (I.) bohemani also differs from C. (I.) longipennis by the darker fringe and margin of the calypter and fore coxae more extensively yellow (head missing in specimen examined).

Cerodontha (Icteromyza) montanoides Spencer

(Figs. 8, 18, 71–75)

Cerodontha (Icteromyza) montanoides Spencer, Reference Spencer1981: 171; Spencer and Steyskal Reference Spencer and Steyskal1986: 89

Type examined: Paratype. UNITED STATES:California: Sagehen Crk, Nevada Co., 11.vii.1975, B. Villegas (1 ♂: NMNH).

Other specimens examined: UNITED STATES:California: Lake Tahoe, 15.viii.1959, A.L. Melander (1 ♂: NMNH); Napa Co., Pope Beach Lk. Berryessa, 16.viii.1957, Mel (1 ♂: NMNH); Prosser Creek, near Hobart Mills, 6300′, 13.vii.1961. J.G. Chillcott (1 ♂; 2 ♀: CNC); Truckee, Nevada Co., 25.vi.1943, P.H. Arnaud (1 ♀: NMNH); 13 km N Truckee, Hwy. 89 at Sagehen Creek (39°26.07′N, 120°12.22′W), 1769 m, sweep vegetation, 15.viii.1999, S.E. Brooks (1 ♀: LEM). Utah: Cedar Brakes, 22.vii.1956, A.L. Melander (1 ♀: NMNH). Wyoming: Yellowstone Park, Dunraven Pass, 28.vii.1934, A.L. Melander (2 ♀: NMNH).

Diagnosis. The brown palpus, brown frons, often medially yellow clypeus, and the male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Frons width 0.38–0.40 mm; ratio of frons width to eye width 1.5–1.6; orbit, each approximately 0.20–0.23 times the width of frons at level of lower ors; lunule large, in the form of a semicircle or slightly higher; frontal triangle apparently extending not further than lower ors; length between ocellar tubercle and margin of lunule 0.15–0.17 mm; base of antennae separated by narrow and slightly elevated keel; clypeus medium-thick with upper margin rounded (Fig. 18); in profile, orbit slightly projecting anterodorsally; parafacial absent or slightly projecting, sometimes forming narrow cheek; usually two inclinate ori (one specimen with three on both sides) and two reclinate ors; distance between upper ori and lower ors usually less than 1.5 times the distance between both ori; gena at midpoint, 0.20–0.26 times the maximum eye height; gena 1.2–1.5 times deeper at hind corner than at midpoint; eye bare. Wing length 2.15–2.5 mm in male and 2.6–2.9 mm in females; distance between r-m and dm-cu 1–1.7 times the length of vein dm-cu.

Colour: Frons yellowish-brown to dark brown, sometimes slightly paler above; orbit brown, sometimes a mixture of pale brown and black (along eye margin and below both ors) (Fig. 8); orbit becoming yellowish at level of ori or below ori; frontal triangle only slightly paler than frons; lunule, face, and gena yellow (antennal foveae sometimes darker); antennae brown except for partly yellow scape (anteriorly); palpus brown; clypeus completely black or narrowly to widely yellow centrally (Fig. 18). Thorax and abdomen greyish-brown; legs brown (including fore and mid-coxae), except all knees narrowly yellow: fore femora yellow for a distance of 0.13–0.20 times the length of femora. Calypter, including margin and fringe, brown.

Genitalia. Distal tubules curving dorsally at an angle of 90° to mesophallus. Distal tubules with a length of about 0.22–0.24 mm (taken vertically from lowest point to highest point). Distal tubules slightly to strongly diverging in ventral view (Fig. 72). Hypandrium in lateral view with a bulbous ventral projection as illustrated for C. (I.) griffonensis (Fig. 55). Inner margin of epandrium with approximately six spines (not all visible in ventral view) (Fig. 74). Anal projection well developed and cerci shorter than ventral margin of epandrium in lateral view (Fig. 75). Ejaculatory apodeme with broad blade (Fig. 73).

Geographic distribution: Western United States (California, Utah, Wyoming).

Host plant: Unknown.

Comments: This species is so far restricted to the western part of the United States of America. It was previously known only from California. New localities include Utah and Wyoming.

Cerodontha (Icteromyza) pilosa Boucher

(Figs. 9, 76–77)

Cerodontha (Icteromyza) pilosa Boucher, Reference Boucher2008: 560

Type examined: Holotype. CANADA.Yukon Territory: Firth River, 30.vii.1956, E.F. Cashman (1 ♂: CNC).

Diagnosis. The yellow palpus, yellow frons, conspicuously hairy eyes (Fig. 9), and extensively yellow knees (approximately for half the length of femora) differentiate this species from other Nearctic Icteromyza.

Description. This species was described by Boucher (Reference Boucher2008), but additional characters recognized here are as follows: clypeus narrow with upper margin rounded, pale brown laterally and yellow centrally. Fore coxae yellowish apically and mid-coxae partially yellow.

Genitalia. Distal tubules long, recurved towards mesophallus, reaching about midpoint of mesophallus (Fig. 76); apex slightly enlarged and flared. Mesophallus long and narrow, measuring 0.43 mm. Narrow basal tubular projection of mesophallus measuring 0.27 times the length of mesophallus. Hypandrium with two apodemes (as in some longipennis, Fig. 63A). Anal projection well developed. Cerci longer than ventral margin of epandrium in lateral view. Ejaculatory apodeme with blade slightly expanded (Fig. 77).

Geographic distribution. Northwestern Canada (YT).

Host plant. Unknown.

Comments.Cerodontha (I.) pilosa has the eyes conspicuously pilose as in C. (I.) lineella, but the former can be differentiated by having a less pronounced projection of the frons, a narrower gena, a less oblique eye, and more extensively yellow knees. Cerodontha (I.) pilosa is also very similar to C. (I.) longipennis but can be distinguished by its conspicuously hairy eyes, larger size, and longer mesophallus. Only one specimen of C. (I.) pilosa is so far known; its genitalia are on a permanent mount, making it difficult to see potentially diagnostic details such as the spines on the inner margin of epandrium.

Cerodontha (Icteromyza) temeculensis Spencer

(Figs. 10, 78–82)

Cerodontha (Icteromyza) temeculensis Spencer, Reference Spencer1981: 173; Spencer and Steyskal Reference Spencer and Steyskal1986: 90

Specimens examined:UNITED STATES:California: Alamos Creek, S.L. Obispo Co., 22.vi.1948, W.W. Wirth (1 ♂: NMNH); Deep Creek, 25.i.1953, A.L. Melander (1 ♀: NMNH); Palm Springs, 11.iv.1955, W.R.M. Mason (9 ♂; 8 ♀: CNC); Palm Canyon, Palm Springs, 15.iii.1955, W.R. Richards (2 ♂ [including one paratype of C. (I.) churchillensis]; 1 ♀: CNC); Palm Canyon, Palm Springs, 16.iii.1955 (2 ♂; 1 ♀: CNC); 1000 Palms Oasis, Thousand Palms, 26.vii.1955, W.R.M. Mason (1 ♂: CNC); Riverside, 24.ii.1935, A.L. Melander (1 ♂; 1 ♀: NMNH).

Diagnosis. The yellow palpus and frons, the bare eyes, the narrowly yellow femora, the postocellar bristles arising on a yellowish background, a male wing length of less than 2.8 mm, and the male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Frons width 0.30–0.40 mm; ratio of frons width to eye width 1.4–1.6; orbit, each approximately 0.20–0.25 times the width of frons at level of lower ors; lunule moderately large, higher than a semicircle (Fig. 10); frontal triangle sometimes clearly reaching margin of lunule but in some specimens hardly differentiated from frons; length between ocellar tubercle and margin of lunule 0.17–0.20; base of antennae separated by narrow keel; clypeus medium thickness, with upper margin rounded; in profile, orbit slightly projecting anterodorsally; parafacial much reduced; cheek narrow; two inclinate ori, two reclinate ors; distance between upper ori and lower ors about 1.2–1.5 times the distance between both ori; gena deep: at midpoint 0.22–0.30 times the maximum eye height; gena slightly deepest at rear, up to 1.4 times deeper than at midpoint; eye bare or with short scattered hairs; long axis of eye slightly to strongly oblique. Wing length 2.3–2.8 mm in males, 2.75–3.2 mm in females; distance between r-m and dm-cu 1.4–1.8 times the length of vein dm-cu.

Colour: Frons yellow, sometimes slightly brownish anteriorly; orbit, frontal triangle and lunule usually uniformly yellow (Fig. 10) (a few specimens with part of the orbit pale brown at the level of the posterior ors, or at most to the level of the anterior ors); postocellar bristles arising on dark yellow or orange background; face, palpus, and gena yellow (antennal foveae sometimes darker); antennae mostly brown, except scape yellow, and pedicel partly yellow medially especially apically (Fig. 10); clypeus brown, sometimes narrowly yellowish centrally. Thorax and abdomen greyish-brown; legs mostly brown (including fore coxa, which is at most only slightly yellowish apically), but femora yellow distally for about 0.2–0.3 times the length (measurement taken on fore femora), and mid-coxa partially yellow. Calypter yellowish, margin and fringe pale brown to dark brown.

Genitalia: Phallus not strongly curved in lateral view, almost in line with mesophallus (Fig. 78). Distal tubules approximately as long as mesophallus. In ventral view, distal tubules strongly diverging on distal half (Fig. 79). Ejaculatory apodeme with narrow blade (82). Anal projection conspicuously prominent and covered with short pilosity (Fig. 81). Cerci in lateral view extend past the distal margin of the epandrium (Fig. 81). Hypandrium moderately large (Fig. 82).

Geographic distribution: Western United States (California).

Host plant: Unknown.

Comments: This species is very similar externally to the newly described species C. (I.) woodi and to the palaearctic species C. (I.) geniculata but differs mainly in the shape of the phallus.

Cerodontha (Icteromyza) vockerothi Boucher, sp. nov.

(Figs. 11, 19, 23, 83–86)

Type material.Holotype: ♂. UNITED STATES. Virginia: Arlington, vi.1938, J.R. Malloch (NMNH). Paratype:CANADA.Ontario: Mer Bleue, 19.vii.1963, J.R. Vockeroth (1 ♀: CNC).

Etymology: This species is named in honour of J.R. Vockeroth to acknowledge his great contribution in building up the Agromyzidae collection (and other Diptera) of the CNC, and also to thank him for sharing little bits of interesting Diptera stories during my visits to the collection.

Diagnosis: The brown palpus, brown frons, bright yellow lunule, three ori, and the shape of the male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Frons width 0.35–0.40 mm; ratio of frons width to eye width approximately 2.2; orbit, each approximately 0.18 times the width of frons at level of lower ors; lunule large, higher than a semicircle (Fig. 11); frontal triangle hardly differentiated from frons and apparently not reaching margin of lunule; length between ocellar tubercle and margin of lunule 0.15 mm; base of antennae separated by narrow and slightly elevated keel; clypeus moderately thick with upper margin rounded (Fig. 19); orbit moderately projecting anterodorsally (Fig. 23); parafacial reduced; cheek absent; three inclinate ori (one missing on one side in the holotype, but socket present) and two reclinate ors; gena at midpoint, 0.15–0.20 times the maximum eye height; gena only 1.2 times deeper at hind corner than at midpoint; eye bare. Wing length 2.2 mm in male, approximately 2.6 mm in female (wing bent); distance between r-m and dm-cu 1.2–1.5 times the length of vein dm-cu.

Colour: Frons completely brown (Fig. 11); orbit mostly brown but with darker blackish patch below ors and paler yellowish anterior to ori; frontal triangle brown, only slightly paler than frons; lunule, face, and gena yellow (antennal foveae darker); antennae brown except scape and pedicel sometimes partly yellowish anteriorly; palpus brown; clypeus completely brown (Fig. 19). Thorax and abdomen brown; legs brown, except all knees yellow: fore femora yellow for a distance of approximately 0.20–0.23 times the length of femora. Calypter, including margin and fringe, pale brown.

Genitalia. Distal tubules curving dorsally at an angle of approximately 90° to mesophallus (Fig. 83). Distal end of distiphallus with a small pointy projection (Fig. 83). Mesophallus long and narrow. Distal tubules diverging in ventral view (Fig. 84). Hypandrium narrow (Fig. 85), in lateral view with a small bulbous ventral projection. Anal projection small (about half the size of C. (I.) montanoides, Fig. 75). Cerci small, not reaching ventral margin of epandrium. Ejaculatory apodeme with narrow blade (Fig. 86).

Geographic distribution: Eastern Nearctic (Ontario, Virginia).

Host plant: Unknown.

Comments: Externally, this species is most similar to C. (I.) montanoides. The completely black clypeus and presence of three ori of this new species are useful characters to differentiate both species. Their geographical range is also different with the new species known from Virginia and Ontario, while C. (I.) montanoides is restricted to the western United States.

Cerodontha (Icteromyza) woodi Boucher, sp. nov.

(Figs. 12, 20, 24, 87–90)

Type material: Holotype: ♂. UNITED STATES. California: Muir Woods, 7.viii.1915, A.L. Melander (NMNH). Paratypes:UNITED STATES. California: Big Bear Lake, 24.v.1955, A.L. Melander (1 ♀: NMNH); Julian, 10.iv.1980, S.A. Marshall (1 ♀: DEBU). Michigan: Cheboygan Co., Marl Bay, 29.vii.1931, emerged 14.viii.1931, E. Kauffman (1 ♂: NMNH). Washington: Mt. Rainier, Berkeyley Park, 23.viii.1934, A.L. Melander (1 ♂: NMNH).

Etymology: The new species is named in honour of D. Monty Wood to underline his contribution as editor of two large and important works on New World Diptera: the Manual of Nearctic Diptera and the Manual of Central American Diptera. The name of this new species also alludes to the type locality, Muir Woods.

Diagnosis: The yellow palpus and frons, slightly darkened orbit, bare eyes, narrowly yellow femora, a male wing length of over 2.8 mm and the male genitalia differentiate this species from other Nearctic Icteromyza.

Description. Externally very similar to C. (I.) temeculensis, except for the following differences: distance between ocellar tubercle and margin of lunule longer (0.25–0.27); distance between upper ori and lower ors about the same distance or a little shorter than the distance between both ori; in profile, orbit not projecting anterodorsally (orbital plate not visible in front of eye in profile) (Fig. 24), but narrow ring (cheek) present below eye (as in temeculensis); clypeus slightly thicker (shining in holotype, matte in paratypes) (Fig. 20); and slightly larger species (wing length of 2.8–3.4 mm in males, 3.2 mm in females).

Colour: As C. (I.) temeculensis, except lower frons and lunule sometimes brownish; if frons yellow, lunule with upper margin narrowly black; orbit always at least slightly darkened (Fig. 12), usually posteriorly at level of ors, but in one female specimen almost completely brown; postocellar bristles arising on black background; antennal foveae sometimes more extensively brown; clypeus completely dark brown (Fig. 20); femora narrowly yellow: only 0.15 times the length of femora (measurement taken on fore femora). Mid-coxa completely brown.

Genitalia: Overall shape of phallus very similar to that of C. (I.) fuscifrons, with distal tubules forming a big loop and with a distinct smooth curvature near the base of mesophallus (Fig. 87), however, distiphallus and mesophallus longer than in C. (I.) fuscifrons: mesophallus measuring 0.5 mm (in its original bent position). Ejaculatory apodeme with blade slightly expanded (Fig. 89). Hypandrium narrow (Fig. 90). Inner margin of epandrium with three to four spines (Fig. 88). Anal projection, prominent. Cerci extending slightly beyond ventral margin of epandrium in lateral view.

Geographic distribution: United States (California, Michigan, Washington).

Host plant: Unknown.

Comments: This species is externally very similar to C. (I.) temeculensis but the genitalia are distinct, resembling more closely the genitalia of C. (I.) fuscifrons. This similarity is shown by the long recurved distiphallus and the distinct shape of the mesophallus, with a curve at the centre. This is also characteristic of a few Oriental species such as C. (I.) duplicata. Although one specimen was apparently reared (Michigan, emerged 14.viii.1931), no host plant was recorded on the label.