This report contains a record of the trypanosome infections, food and breeding of G. morsitans and G. tachinoides obtained by examining the flies at various foci over a period of fourteen months.

It confirms the fact that the breeding of both species is practically confined to the dry season and follows a period of increased food supply. G. tachinoides is well fed through the rains, except in one month of flood, and starts breeding as soon as the rains cease, owing to its habit of feeding on reptiles. G. morsitans starts free breeding about six weeks later, as its increased food supply is due to the ungulates becoming more available.

G. morsitans does not feed on reptiles, but in times of hunger draws a proportion of its food from birds, the largest proportion recorded being 17 per cent, in one month at one focus. It draws the bulk of its food in this locality from small antelope, large game being scarce. G. tachinoides is much less specialised in its diet, and in the wet season nearly one-fifth of its food was drawn from a group of animals which included man, monkey and dog.

The infection of the flies with T. vivax and T. congolense bears a close relation to the amount of blood obtained from antelope, and consequently morsitans is in general nearly four times as heavily infected as tachinoides. Infections with T. brucei and T. gambiense are scarce in this locality. Trypanosome infection rises just before the main breeding season in morsitans in all localities and in tachinoides in places where the fly is largely a mammal feeder. The proportional infection in general falls in the season of most rapid breeding, owing to masking of the actual rise by the number of young flies examined. It rises rapidly when breeding ceases. The total infection is reduced when fly food is hard to obtain, in the time of long grass and flood, owing to T. vivax infections dying out when the flies are starved.

It is shown that in some cases T. grayi may be obtained by tachinoides when it feeds on Varanus, and a somewhat similar infection in the laboratory may be obtained by feeding the flies on toads.

It is shown that in some cases T. grayi may be obtained by tachinoides when it feeds on Varanus, and a somewhat similar infection in the laboratory may be obtained by feeding the flies on toads.

There is just an indication that postponement of grass burning may interfere with the free breeding of morsitans and in some cases that of tachinoides. This possibility is to be tested.

The experiment of excluding game and pig from one of the dry season foci of the flies by means of fencing will be carried out.

The purpose of this paper is to direct attention to the possibilites of sodium fluoride as an insecticide. Recent investigations of this salt as a stomach poison, which I have undertaken with cutworms and locusts, as well as its few but successful previously known uses as an insecticide against fowl-lice, Mallophaga on mammals, cockroaches, and earwings, indicates that sodium fluoride may, in a number of cases, replace the use of arsenical poisons. During the past decade the use of arsencial insecticides has increased rapidly. We are at present threatened with higher prices and possibly with a shortage of arsenic, a situation accentuated by the present cotton-boll weevil programme of the United States of America, which involves the use of tremendous quantities of arsenicals. Any cheap stomach poison effective against insects and promising as a substitute for arsenicals should therefore be of considerable interest to the entomologist and to the farmer, especially if it carries the additional advantage of being considerably less poisonous to man, stock and birds. Sodium fluoride meets these requirements.

♂. Pale greyish stramineous. Antennae clothed with short hairs, and with indefinite brownish rings. Face smooth. Fastigium of vertex cylindrical, sulcate above, with the apex rounded, and slightly inflated, viewed in profile almost truncate. Pronotum callosely rugulose; its discovery feebly saddle-shaped, with the median carina scarcely perceptible near the hind margin, which is roundly truncate; the two transverse sulci deep, the anterior one feebly bisinuate, the posterior one broadly arched; anterior margin rounded; lateral lobes sloping, somewhat longer than broad, with the anterior angle obtuse, the posterior one very obtuse and rounded, and the hind margin strongly sinuate, with a deep humeral sinus. Elytra nearly twice as long as the abdomen, with the veinlets whitish green. Prosternum armed with two not long, pointed, somewhat divergent spines. Mesosternal lobes small, rounded; metasternal lobes forming together an equilateral triangle with the angles broadly rounded. Front and middle femora armed with 0–3 small black spinules on the inner lower margin (hind legs missing in the type). Cerci (fig. 1, C) round, feebly incurved, with the apex attenuate, distinctly incurved, pointed. Subgenital plate (fig. 1, A, B) very long and narrow, slightly recurved; the lower surface almost flat, with an incomplete median ridge and two more distinct sublateral ridges running throughout the plate to the bases of the styli; the latter short, cylindrical; hind margin of the plate acutely and deeply excised between the styli.

In connection with the development of cotton growing within the Empire, it has been found necessary to circulate many small batches of experimental cotton seed; and as a number of these batches pass through this country, it has been deemed advisable to disinfect them against pink bollworm (Platyedra gossypiella, Snd.) and other insect pests.

This genus was founded to contain the single species— filicum of Maskell, which had been referred by that author to the genus Lecanopsis.

The apparatus here illustrated (Plate i) has been devised by the writer for photographing mosquitoes by the method generally known as “low power photomicrography,” in which a long extension camera fitted with a short focus photographic lens is employed.

This work was commenced in 1919 and continued in 1920 and 1923. The writer's thanks are due to Prof. H. Maxwell Lefroy, who provided facilities for the carrying out of the work at Westbrook House, Heston, and showed great interest in its progress. Publication of the results has been delayed in the hope that further experiment could be made in the near future.

In Bulletin No. 28 of the Technical and Scientific Service of the Ministry of Agriculture of Egypt I described a new type of light trap for collecting insects which had the advantages that the insects were rapidly killed in good condition for identification, that the light was visible in all directions, and that it could be used with either electricity or acetylene by an untrained worker.

The small collection of CERATOPOGONINAE described in this note was made by me last December (1923) during a short voyage on the Nile from Cario to Assuan and back. The steamer on which the voyage was made anchored at night, and being brightly lit, attracted large numbers of midges which congregated on the woodwork in the neighbourhood of lamps and were thus easily secured. The collection, which was brought home to England before being examined, was not rich in CERATOPOGONINAE, but an account of such species as were contained in it may be of some interest, because little appears to be known about the occurrence of these midges in Egypt.

♀. Black, except as follows: funicle piceous, base of 6th (8th) tergite dark brownish; scape, pedicel and ring-joint, trochanters, femora and tibiae ferruginous; tarsi much paler; pubescence pale brown to nearly golden (on head) and on funicle paler. The head and thorax somewhat dull; abdomen shining, except on the ventral overlap of tergite 4(6) and on tergite 6(8).

With the new material received from the Imperial Bureau of Entomology through the courtesy of Dr. Guy A. K. Marshall, I am now able to complete my previous notes on the Ethiopian Trypaneidae.