Four years on from the 2nd Edition of this useful introductory text this book remains good value at a modest price rise of only £5.00. In twenty chapters Professor Service follows his well-worked and consistent pattern in each chapter by describing the morphology of each group of vectors, followed by life-cycle, medical importance and control. The further reading information provided at the end of each chapter has been updated wherever relevant. In addition, as an aide-mémoire to revising, certain key words now appear in bold. In many groups, new information is provided on the numbers of species now described. In the case of mosquitoes this is now 3300, an increase of 100 and there are now 4 further genera including Ochlerotatus, a previous subgenus of Aedes. Outstanding developments in control include the innovative development of manufactured bed nets that are impregnated with synthetic pyrethroids, which are designed to release the active molecule over periods as long as four years. Mike Service is, however, cautious, and warns that despite our great hopes for this new development, the incidence of resistance to pyrethroids is a realistic potential threat to its success. In similar vein it is noted that mosquitoes in the laboratory have been observed to develop resistance to the bacterial insecticides Bacillus thuringiensis and B. sphaericus. This has not as yet proved to be a problem in the field with mosquitoes, but experience with agricultural pests, such as the diamondback moth, indicates the need for vigilance.

The metacercaria shown in Fig. 1 was obtained in the laboratory from Gobies (Gobius ruthensparri Euphras.) experimentally infected with a Pleurolophocerca cercaria from Peringia ulvae. This cercaria is regarded as the most interesting of all the Heterophyid larvae infecting this snail. It has been referred to briefly in a previous publication (Rothschild, 1938). It differs from typical Opisthorchid cercariae in the following characteristics:

(1) The lateral fin-folds are continuous and extend the whole length of the tail. The dorso-ventral fin-fold is reduced.

(2) The oesophagus and intestinal caeca (in addition to the pharynx) can be clearly made out.

(3) The cuticle is more heavily spined.

(4) The ventral sucker is better developed.

(5) The penetration gland ducts (fourteen in number) are not arranged in such definite bundles.

(6) Three acicular boring spines are present in the oral sucker.

In other respects the cercaria possesses the usual characters of the group.

I was much interested in the paper on Herpetomonads in mice in the June number of Parasitology (Fantham and Porter, pp. 128–132). In 1904 or 1905 when working at trypanosomiasis at Khartoum I came across a flagellate in the peripheral blood of a gerbil (Gerbillus pygargus) which was clearly not a trypanosome and the nature of which I was unable to identify.

Vesiculated protoscoleces (VP) were produced by culturing freshly collected protoscoleces from Echinococcus granulosus horse liver hydatids in RPMI 1640 monophasic medium at 37°C for 18 days. Half of the VP were used as such, the other half used after killing them by freeze—thawing. Nine-day-old chicken heart fragments (CHF) were cultured in MEM at 37°C for 72 h. Subsequently, CHF were put together with live and dead VP, respectively, for up to 53 days, on a semisolid medium consisting of agar, Ringer's and MEM. Time-dependent histological observations revealed that dead VP were surrounded by CHF cells. Dead VP tissue was eventually internalized and disintegrated in about 1 week. Live VP penetrated into the CHF tissue and further developed into small hydatid cysts, located within the boundaries of the experimental ‘host’ tissue. The amorphous-looking contact region PAP-stained positively only with anti-E. granulosus serum and not with anti-CHF serum; it was considered identical to the normal laminated layer. The invasion of VP in CHF tissue proved to be different from a tumour or a bacterial invasion: it was concluded that the confrontation of VP and CHF had resulted in an ‘in vitro cohabitation’ rather than in an ‘in vitro infecion’.

1. A short note is given on Pterygosoma hystrix Lawrence, 1935, amplifying the original description and extending the known range of variation.

2. The hitherto undescribed male, larva, protonymph and deutonymph of Pterygosoma gerrhosauri Law, 1935, are described and figured.

3. The protonymph and deutonymph of Pterygosoma bicolor Law, 1935, are described and figured, together with a record of variation in the female.

References to dipterous parasites of Diptera are rare in the literature. Bombyliids of the genera Villa and Thyridanthrax have been reared from the puparia of Glossina; Hemipenthes morio L., from the tachinid Parasetigena segregata Rond., and the sarcophagid Sarcophaga affinis Fall.; Argyramoeba varia F. from the tachinid Sturmia inconspicua Mg. The phorid Hypocera incrassata Mg. was found by H. M. Morris in dead and unhealthy larvae of Bibio marci L. Only one larva of Hypocera was obtained from each specimen of Bibio, and the account given by Morris suggests that this species is a true parasite. The evidence is, however, not absolutely conclusive and further study of this interesting species is desirable. The same thing must be said of E. E. Edwards' record of Aphiochaeta brevicostalis Wood, as a parasite of Tipula sp.

We received from Dr W. H. Thorpe a remarkable Eupelmid bred from the large Coccid, Aspidoproctus maximus Newstead, in East Africa. As Dr Thorpe has been able to make some interesting observations on the life history of this parasite, I have been asked to study it specially. It differs from all other known species of Eupelmus from Africa, and I am giving here a description of that species.

During the months of September, October, November and December 1917 I collected 1250 different specimens of fresh-water snails from various parts of the Transvaal, more especially from the sources of the Vaal and Crocodile rivers. All the larger specimens I submitted to microscopic examination for possible infection with cercariae. From the mud at the bottom of the Mooi river at Potchefstroom, which is a tributary of the Vaal, I came across some very finely preserved specimens of Unio caffer Krauss, a large number of which contained small pearls attached to the shell. The amount of lime in the bed of this river probably accounted for the perfect state of the umbones of these Uniones. Amongst the small stones at the bottom of the river I collected some remarkably large specimens of Corbicula radiata Parreyss. The river also contained some specimens of Pisidium, a much smaller variety, not yet identified. On the decomposing rushes at the edge of this river there were numerous specimens of Ancylus, for which Mr Henry C. Burnup has suggested the name Ancylus cawstoni; I have seen similar specimens at Klerksdorp and in the Hex river at Kustenburg, a branch of the Little Crocodile. All these specimens were free from cercarial infection.

The genus Neoaplectana now contains eleven species of nematodes. All are associated with insects. A brief review of the history of the genus is given. An undescribed species referred to as DD-136 is compared with one other species in the genus Neoaplectana. It is very similar to the description given for N. carpocapsae Weiser, and it is concluded that it is probably this species.

The results described above indicate that quinanil and the compound 2 (p-dimethylaminoanil)-β-naphthoquinoline methochloride might be successfully used as selective reagents for the isolation of insect flagellates of the genus Leptomonas.

The actual concentrations, which might be successfully used in the culture media, will show some variation according to whether the flagellate is adapted, at the time, to luxuriant growth in the media used. For example, in preliminary experiments, the Leptomonas from Polietes and Calliphora grew better in Locke serum agar than in bouillon, and quinanil was more toxic in the latter than in the former. In the present experiments the reverse held, but in later ones, not here recorded, where the flagellates have again grown more abundantly in Locke serum agar, growth regularly occurs in 1/6000 concentrations of quinanil in this medium. There is little doubt from other results, not yet published, that some Leptomonas forms can be made to show modification of cultural requirements through adaptation. It is probable therefore that in the attempted isolation of fresh forms from the gut of the insect, several kinds of media might have to be employed.

After this work was completed, in several attempts made to purify laboratory-contaminated cultures, success was attained by following the suggested methods, using quinanil and 2 (p-dimethylaminoanil)-β-naphthoquinoline methochloride. The compound 113 was even less toxic to the Leptomonas forms in media than was the compound 52, but its bactericidal action was correspondingly weaker. The few experiments conducted in the absence of media indicated that this substance might have proved very useful, but unfortunately the material gave out and further supplies were not available. In the preliminary treatment of gut contents, acriflavine, owing to its apparently bacteriostatic action, might prove of some value for destroying organisms of the Bacillus prodigiosus type.

Consideration of the results obtained with gentian violet, brilliant green, and the two anilquinolines, 2 (p-dimethylaminoanil)-6-acetylaminoquinoline methochloride and methosulphate, suggests that these compounds are of no use as selective bactericidal substances permitting the growth of Leptomonas forms. The combined action of two or more of these substances has not yet been studied.

As our results indicate, little success is to be hoped for in this direction with the Leishmania forms, which are extremely susceptible to the toxic effects of all the substances employed. Two points of interest were obtained from these results. It might be noted that Leptomonas ctenocephali reacted in a similar manner to the Leishmania forms but that Leishmania tropica (“Baghdad”) behaved like a Leptomonas form. This strain appeared similar in all respects to the other Leishmania forms, but it was the only one readily acclimatised to media containing no blood. Its morphology also showed some modification after a time.

We are greatly indebted to Dr St John-Brooks, Curator of the National Collection of Type Cultures, and to Prof. S. Adler of the Hebrew University, Jerusalem, for certain of the cultures of Leishmania and Leptomonas used, and also to Dr K. E. Cooper for the gift of the anilquinoline derivatives and for much helpful advice.

One of us (F. C. H.) has also been in receipt of grants from the Medical Research Council, and he would like to take this opportunity of expressing his thanks to that body.

Previous records and descriptions of the fungus known as Acladium castellanii, a human pathogen in the south-east of Asia and Europe and in Brazil, are cited and an account is given of its morphology when studied in culture on organic media.

It is concluded that it is closely related to, and perhaps merely a strain of, the widely distributed Sporotrichum schencki, the commonest cause of human and equine sporotrichosis, and that the term acladiosis as denominating a distinct disease should be deleted.

Schistosomiasis is a chronic debilitating disease which accounts for considerable human mortality and morbidity and is second only to malaria in its prevalence and severity. Despite several years of concentrated effort to combat the disease with molluscicides and chemotherapy, schistosomiasis is still spreading, and it is thought that 500 million people are currently exposed to infection (larotski & Davis, 1981).

The ultrastructure of the developing excretory system of Prosorhynchoides gracilescens and Prosorhynchus squamatus cercariae is described. The development pattern was similar in both species. In early embryos the two main collecting tubes were composed of a layer of cells which were wrapped around the lumen. Later, the tubes fused and the excretory epithelium of the fusion zone and that of the lateral caudal ducts became a syncytium. The collecting tubes in the cercarial body retained their cellular organization. As the tails grew, additional excretory pores were formed in the tail stem where thickened portions of the caudal duct epithelium contacted the surface tegument. Following this, the distal portions of the lateral caudal ducts lost contact with the primary excretory pores and progressively degenerated. Excretory atrium development started with differentiation of secretory active cytons peripheral to the fusion zone. These cells gave rise to cytoplasmic extensions that penetrated the fusion zone wall to eventually form a continuous cytoplasmic layer. This layer eventually replaced some of the fusion zone excretory epithelium and became the lining of the excretory atrium. The anterior end of the fusion zone differentiated into an excretory bladder and a short posterior portion gave rise to the caudal vesicle.

1. Isolated unmated female body-lice were worn in pillboxes between the skin and the clothes. They were kept constantly on the body but, by a simple device, groups of ten were permitted feeding periods of different length. These groups were fed for 4, 8, 12, 16, 20 and 24 hr. per day respectively. Another group of ten were never allowed to feed after the last moult.

2. Some of the figures for egg yield were high. Lice in the 24 hr. group were able to maintain a rate of ten eggs per day for 4−5 days at a time.

3. No significant difference in longevity or rate of egg-laying was found to exist between the 12, 16, 20 and 24 hr. groups nor between the 4 and 8 hr. groups but a pronounced and significant difference exists between the 8 and 12 hr. groups. Below 12 hr. there is a sharp fall in longevity and rate of egg production. The unfed group all died, without laying, on the third day.

4. The rate of laying as shown by the mode increases progressively with increase in time allowed daily for feeding.

5. With regard to the mean eggs per louse the position is less clear. It is felt that the 24 hr. group may differ significantly from the 12, 16 and 20 hr. groups but this is uncertain.

Ixodes arvicolae Warburton was collected at 2-monthly intervals from January 1961 to August 1962 on a total of 226 Apodemus sylvaticus and 264 Crocidura suaveolens cassiteridum in the Scilly Isles. Twenty-one adult females (out of a total forty-two ticks) were found on Apodemus and one adult female (out of a total 106 ticks) on Crocidura. No adult males were found. Ticks were collected from the hosts throughout the year, but in Crocidura there was a suggestion of greater frequency for larvae during the summer. I. arvicolae was also found on Mus musculus in the Scilly Isles and on Microtus agrestis in Cornwall.

We wish to thank Professor D. R. Arthur of King's College, University of London, for identification of the ticks involved in this study, and Dr Alec Milne of the University of Newcastle upon Tyne for helpful criticism of the manuscript.

1. The assumptions underlying the current methods of determining the efficiency of drugs or a mixture of drugs as an anthelmintic are set out.

2. The method of assessing the efficiency of a given drug or mixture of drugs, as used by Seddon and Ross, is cited and objections to its value are given.

3. A method is suggested whereby the mean efficiency of a drug or mixture of drugs can be assessed, in terms of the initial and residual infestation of selected animals.

4. In the light of the suggested method, Roberts' data for the efficiency of various drugs and mixtures of drugs, as specifics against H. contortus infestation in sheep, are fully investigated.

Among other cestodes collected by me some years ago were specimens of the prismatic malformation of a tape-worm which I have recently examined. This abnormality in the taenioid group of cestodes has been frequently reported in Europe, especially in Taenia saginata, since Andry's case was first described in 1700. This malformation is known as Taenia ‘tridre,’ ‘triquestre,’ or ‘prismatique’ in French; as ‘dreikantige’ in German, and as ‘tri-radiate’ or ‘prismatic’ in English. But as far as my knowledge goes, we do not find a full description of any such abnormality in Taenia crassicollis, though a brief description of it was given by Bremser in 1819 and 1824. It is now recorded for the first time from Japan.

Testes in the male early acanthella of Moniliformis dubius are cellular. The testes in the middle and late acanthellae and cystacanth stage also contain individual cells but these are embedded in a compact supporting syncytium which also forms the boundary of the testis. The testes are embedded in the cytoplasmic wall of the ligament sac in the early acanthella but after this stage they become exposed in the cavity of the sac when the surfaces of the testes become covered by a surface coat. Certain cells adjacent to testes primordia in the early acanthella appeared to have formed rudiments of vasa efferentia in the middle acanthella.

A description is given of a new species of paruterinid Cestode, belonging to the subfamily Paruterinae Fuhrmann, 1907, of the family Dilepididae Fuhrmann, 1907, to which the name Lallum magniparuterina gen. et sp.nov. is given. It is parasitic in the intestine of the common teal, Nettion crecca Linn.