For some years prior to 1935, the cotton Capsid of Uganda, which is now known to occur in several other parts of Africa also, was called Lygus vosseleri, Popp. In 1935, Mr. W. E. China of the British Museum (Natural History), after examining type material, published a note synonymising vosseleri of Poppius with simonyi of Reuter and concluded that the cotton Capsid previously identified by him as L. vosseleri, Popp., must therefore be called L. simonyi, Reut. This latter name has been in general use for the cotton Capsid since 1935 and is very widely known because of the great importance of the insect as a pest of cotton.

Four insect parasites of the carrot fly have been encountered and of these three have been identified as Dacnusa gracilis, Loxotropa tritoma, and Aleochara sparsa. The fourth is a member of the genus Kleidotoma, species not yet ascertained.

The life-history, development and host relations of D. gracilis and L. tritoma are given together with data on their distribution and range of parasitism.

L. tritoma also occurs as a hyperparasite of D. gracilis but this appears to be quite fortuitous.

Experimental evidence is brought forward to show that the first instar larva of L. tritoma goes into a diapause in early July, that a period at a low temperature is necessary to break this and hence development is only completed in the following spring.

A description is given of the three larval stages of A. sparsa.

Brief reference is made to the Kleidotoma sp. which appears to be of rare occurrence.

The following discussion is devoted chiefly to toxicological studies, but in order to make the picture more complete, other methods of control of Capnodis and their practicability in the light of the studies presented in three earlier papers will first be referred to briefly.

1. Owing to the history of yellow fever in the Sudan and the lines of communication which traverse the country, a general survey of the mosquitos, particularly the Culicines, is of practical interest. The known potential vectors of yellow fever are listed.

2. Observations on the man-biting or man-ignoring habits of some species are recorded and also notes on the bionomics of Taeniorhynchus africanus, T. uniformis, Aëdes aegypti and other species.

3. For purposes of description the country is divided into sub-divisions of the recognized faunal areas and notes are given on the Culicines of each.

4. Brief observations are made on mosquito control measures against yellow fever.

(1) Sprays that are atomised and mingled with air were unsuitable because they were wasteful in both material and labour.

(2) Knapsack oilers and modified stirrup pumps were efficient. Where labour is cheap hand-operated sprayers of this type are more economical than motoroperated machines.

(3) The relation between mosquito mortality and infectivity is discussed and it is calculated that any treatment which produces 75 per cent. mortality among the mosquitos exposed to it should effect malaria elimination.

(4) The effects of a DDT emulsion were much more durable than those of a similar quantity of DDT in kerosene solution. The difference was much less marked when Gammexane was used. Emulsions will probably displace kerosene solutions as vehicles for the application of residual films.

(5) The persistence of the effects of DDT was markedly increased by increased dosage, so that it will be most economical to apply DDT in heavy doses at long intervals.

(6) The persistence of Gammexane effects was not greatly increased by increased dosage because it evaporates much more quickly than DDT. It is not likely to be effective for much longer than 10 weeks.

(7) Treatments with DDT were usually effective against A. minimus for about twice as long as against A. vagus or Culicines, but treatments with Gammexane had similar effects on all species.

1. Mosquitos often recover completely after showing the preliminary symptoms of DDT poisoning.

2. The effect of contact with DDT on the activity and distribution of mosquitos has been studied in a small cage, exposure times being kept below that necessary to kill the insects.

3. The duration of single resting periods on DDT-treated surfaces was several times shorter than resting periods on untreated surfaces, provided the mosquitos had had no recent access to DDT.

4. Mosquitos that had been in recent contact with DDT rested only slightly longer on untreated than on DDT-treated surfaces.

5. Mosquitos excited by DDT moved preferentially toward light.

A bug identified as Aphanus littoralis, Dist., but believed to be synonymous with A. sordidus, F., was found infesting stored ground-nuts at Yola, Nigeria. It had not hitherto attracted attention in this country, but was found later to be recognised by native farmers as associated with ground-nut plants drying in the fields at harvest.

The nuts concerned were in war emergency mud and thatch stores which were much cooler than the (uninfested) corrugated-iron stores normally used. This difference is believed to have favoured the infestation.

The adults and nymphs cause damage by sucking the oil from the kernels. Loss of weight and germinative power, and development of free fatty acids and rancid and bitter taste follow. It was found, however, that bugs could not penetrate more than three inches or so into the bulked kernels, so damage was not extensive.

1. An onchocerciasis area in South Kavirondo, Kenya Colony, 65 square miles in extent, has been freed from Simulium neavei.

2. The fly was eliminated by the periodical application of DDT emulsion to all infested rivers and streams in the locality. Details of technique are described.

3. Most aquatic life, other than this species of Simulium, had returned to the treated streams, three months after the last application.

4. A microfilaria index of 37 per cent. in children aged four to eight was established as a base-line for future surveys.

In the course of a study of the biology of the Buprestid, Prospheres aurantiopictus, Cast., in Australia, Mr. A. R. Brimblecombe has obtained from the eggs an interesting small Chalcid belonging to the family Encyrtidae.

Several Encyrtid parasites of insect eggs are already known. In Australia Ovidencyrtus pallidipes, Girault, parasitises Reduviid eggs, Tetracnemella megymeni, Dodd, and T. hyalinipennis, Dodd, Pentatomid eggs, and Cheiloneurus viridiscutum, Girault, has been bred from those of cockroaches. In Hawaii the genera Ectopiognatha, Perkins, and Fulgoridicida, Perkins, are found parasitising the eggs of Homoptera. In addition Leefmansia bicolor, Waterston, has been bred from the eggs of the Orthopteron, Sexava sp., in Amboina and Leurocerus ovivorus, Crawford, from the moth, Amathusia phidippus, L., in Java. But most of the Encyrtid egg parasites belong to the genus Ooencyrtus, Ashmead, and it is among them that is placed the only other species known to breed in the eggs of a Coleopteron, Ooencyrtus batocerae, Ferrière, from Malaya. Another species, Tyndarichus rudnevi, Nowicky, is said to have been obtained from the eggs of Cerambyx cerdo, L., in Russia, but as the species of Tyndarichus are generally considered to be hyperparasites, the real parasite of this European Longicorn is still uncertain.