The potentialities of Siam as a field for discovery have hitherto been almost entirely neglected by collectors of Diptera, and in consequence, apart from an occasional description of a new species, little or nothing has been published upon the Siamese representatives of this Order. It follows that the only available method of making determinations of such material is the exceedingly laborious and wearisome one of reading through descriptions of the older authors like Wiedemann and Macquart, which, though based on types collected in other parts of the Oriental Region, may possibly be found to apply to one or other specimen from Siam.

For some years after the intensive study of mosquitos began in tropical countries, surprisingly little interest was taken in the European species, particularly those of Northern Europe. Ficalbi had published his monographic revision in 1896–99, but from then until 1914 very little further had been done; the adults were assumed to be more or less known, though very few of the larvae had been described. Since 1914, however, a great deal of work has been done all over Europe, bionomic as well as systematic, and considerable advances have been made in every branch of our knowledge of these insects.

Head and thorax black; abdomen bright orange-red; tegulae red; antennae clear orange-red, the two apical club joints darker, the scape darker and varying to black; posterior legs, including the coxae, clear orange-red; anterior and intermediate coxae black, their femora and tibiae more or less brown or fuscous, their tarsi red.

♂♀.—Black; the head and rostrum with thin blue-grey scales; the prothorax with rather sparse dull blue scales on the dorsum, the sides entirely clothed with dense metallic green scales; the disk of the elytra as far as stria 4 covered mainly with blackish scaling, more or less interspersed with green scales, which are sometimes denser along the suture; beyond stria 4 the sides are clothed with dense pale green scaling almost to the margin, the inner edge of the green area being very irregular; the lower surface with dense greyish green scaling.

During the months of May and June 1921 I investigated the cause of the serious losses that had occurred among the rose-trees (especially Rosa damascena, Mill.) which are extensively grown in Bulgaria for making attar of roses. The conclusion arrived at is that the cause of the general decline in rose culture is inadequate nourishment of the plants, owing to an insufficient amount of humus and nitrogen in the soil, aggravated by the entire neglect of manuring by the growers. But the immediate cause of the death of thousands of rose-bushes has proved to be certain galls that are to be found on the stems, reaching 2–3 cm. in length and sometimes twice as thick as the normal stem.

It has been stated by Malloch and other authors that the superficial differences between the various species of Simulium in the adult stage are often so minute as to be discernible only after a very careful study of the genus. Previous studies had led the writer to believe that the characters of the pupal respiratory filaments would prove to be of constant specific value, but further investigation has caused this view to be modified with regard to the actual branching, though the structure of the chitinous wall and the general appearance still seem to be constant specific characters.

Head with the integument rather light yellowish, especially when viewed from in front. Erect scales mostly brown, a small area of white ones in the middle towards the front, and in front of these a few long, narrow recumbent scales, not forming a definite frontal tuft. Many light brown bristles between the eyes; border bristles dark. Antennae with the basal joint yellow; in female with a few small scales on the second joint; male plumes light brown. Female palpi very slightly longer than the proboscis, thin, with appressed scales; narrow whitish rings at the tips of the first three joints, just extending on to the bases of the succeeding joints; tip of last joint dark. Second joint slightly longer than the first, slightly shorter than the third and fourth together; fourth joint less than half as long as the third. [Male palpi missing.\ Proboscis dark, except for the labella.

The following paper deals with insect pests of various minor crops and fruit trees in the Colony of Mauritius. The damage caused by most of the pests dealt with is often not very apparent, as many of these crops are not grown extensively, and have not been the object of any special investigation up to the present. If extensive cultivation of any of these should be undertaken, it is clear that there might be created a new environment favourable to increase of the insects, and that the pest problem would then have to be dealt with seriously. Our knowledge of these pests is very deficient, as their life-history and habits have never been studied in detail locally. It is also quite probable that extended cultivation may bring to light many potential pests which at present escape our attention.

Some account of work on the egg-parasites of the coffee bug in Kenya Colony has already been published in a bulletin of the Department of Agriculture of that country.

To entomologists in India the three species of mango Jassids—Idiocerus niveosparsus, I. atkinsoni and I. clypealis—are fairly well known, both on account of their wide distribution and also on account of the serious damage they do to the mango crop. In the course of our studies on these important orchard pests we have within the past three years come across three natural enemies of the adult hopper and one of the nymph; These are (1) a Pipunculid fly; (2) a Stylopid—both internal parasites; (3) an Epipyropid moth—an external parasite of the adults: and (4) a Dryinid wasp—an external parasite of the nymphs.

During 1919–20 an investigation into the habits of A sterochiton (Aleurodes) vaporariorum, Westw., was being carried out at the Lea Valley Experimental Station, Cheshunt, with a view to controlling its attacks on tomatoes under glass. The station exists for the study of scientific problems connected with the glasshouse industry, and as the staff is small, the work is necessarily confined to strictly economic lines. Points that appear in the course of the investigations cannot be followed to their ultimate conclusion in these earlier years of the station's existence if they seem to be of theoretical rather than of practical importance. The following notes relate to such a problem, which it has been decided to record, though in a very unfinished state.

This is the first of a series of papers based on results of breeding experiments and on observations in the field. It is hoped that a full inventigation of the biology of this species will be of value in elucidating the many difficult biological problems of the Aphididae.

It has been found difficult to understand how such a fragile creature as an Anopheline larva could withstand the force of a strong current of water. In the following article it is proposed to explain the phenomenon on anatomical grounds.

Male.—General coloration fuscous, with the vertex of the head, pectus, underside of abdomen, anal region, legs and base of antennal shaft mouse-grey. Fore-wings, above, covered with mouse-grey scales, amongst which are scattered irregular patches of fuscous-black scales, these predominating but forming no definite pattern; beneath, covered more uniformly with fuscous-black scales, except in the region between the first anal vein and the inner margin, which is covered with narrow elongate oval mouse-grey scales. Hind-wings above and beneath covered with fuscous scales, the inner margin furnished with long fuscous hairs. Cilia of both wings fuscous-black.

Head.—Eyes dark red; vertical triangle black, frons dull black, lower part with a somewhat quadrate greyish dust spot; face dull black, lower half appearing grey when viewed from above. Antennae dull yellowish, third joint distinctly pointed, moderately long and almost sub-triangular. Occiput moderately produced behind eye margins, black, with a little grey dust. Thorax moderately shining black, middle of dorsum with yellowish brown dust and a little pale pubescence; pleurae blackish, with some greyish dust. Abdomen shining black; a very little yellowish pubescence towards sides: genitalia with a yellowish tinge. Legs mainly yellow; coxae black, also a broad median band on femora (possibly incomplete in some individuals); tarsi darker towards tips; all femora with a row of very small bristles on about apical half of underside. Wings clear; stigma very pale yellow; anterior crossvein at about two-fifths of the discal cell; halteres yellowish. Length, 2·5–3·5 mm.

Caterpillars on flax in Kenya Colony are farm pests of the first rank. They belong to more than one species, but the one most commonly reared from material from the field is Phytometra (Plusia) orichalcea, F.; Heliothis obsoleta, F., is also met with.