A cage colony of Anopheles pharoensis, Theo., was established in September, 1943. The methods used were mainly those described by Hackett in his paper on the Malaria Station in Tirana, read at the Amsterdam Malaria Congress in 1938.

Damage to citrus fruits by Noctuid moths is known to occur at Ibadan and Agege (about 14 miles north of Lagos). The majority of the observations recorded in this paper were made on Moor Plantation, Ibadan, during the 1938 and 1939 seasons. Box (1942) describes the crop ripening, in the Gold Coast, between April and August as the Main crop, and that ripening between September and December as the Mid crop; in Nigeria, the bulk of the citrus ripens during the latter period, which is known as the Main crop. In this paper the terms wet season and dry season crops are employed.

The practical results achieved in the past twenty-five years' work on the major insect pest problems of Mauritius are discussed.

The major insect pests studied are the white grubs of sugar-cane, Clemora smithi (= Phytalus smithi) and Oryctes tarandus; the sugar-cane moth borers, Proceras sacchariphagus, Sesamia vuteria, and Argyroploce schistaceana; the coconut scale-insect, Aspidiotus destructor; the pineapple mealybug, Pseudococcus brevipes; the cochineal insects of the prickly pears, Dactylopius tomentosus and D. indicus; fruit-flies; the biting flies, Stomoxys nigra and S. calcitrans; the red ant, Solenopsis geminata; the black ant, Technomyrmex detorquens; and termites.

The actual status of these pests is given in detail. Clemora smithi, which was first recorded in 1911, is still a major pest of sugar-cane in spite of the 43 species of parasites and 2 species of predators introduced to check it. Oryctes tarandus very seldom causes severe damage now to sugar-cane plantations. It is a sporadic pest, and has been definitely held in check since the Scoliid wasp, Scolia oryctophaga, was introduced from Madagascar in 1917.

The status of the three moth borers of sugar-cane and that of their parasites is fully dealt with. Of the five species of parasites introduced from Ceylon and Madagascar in 1938–40 to control Proceras sacchariphagus, only one has so far been recovered and its beneficial effect is very limited. An account is given of experiments on the mass liberation of the egg parasites, Trichogramma australicum and T. evanescens. The results were in both cases deceptive. The spotted borer, P. sacchariphagus, is a major pest of sugar-cane in some localities and further introductions of parasites from other cane-growing countries are recommended.

The coconut scale, Aspidiotus destructor, which, since 1927, threatened all the coconut plantations of the Island, is now under control, owing to the introduction from Ceylon and Java, respectively, of the predacious Coccinellids, Chilocorus nigritus and C. politus. The bionomics of the various parasites and predators of this scale in Mauritius are fully described.

A historical review is given of the introduction of the cochineal insects of prickly pear, Dactylopius indicus and D. tomentosus in the Island. The completely successful eradication of Opuntia tuna and O. monacantha, by these two Coccids is given as a typical example of the biological control of noxious plants by insects.

The pineapple mealybug. Pseudococcus brevipes, which is responsible for wilting disease, is considered to be one of the factors limiting the development of the pineapple industry in Mauritius. Spraying with a diesel-clay emulsion, though checking this pest, is limited in its application. Further introductions of parasites and predators are desirable.

The common white mealybug, Icerya seychellarum, is still a major pest of orchards and ornamental plants in spite of the presence of the local Coccinellid predators, Rodolia chertnesina and Exochomus laeviusculus. Practical control can be achieved by the use of banding grease coupled with the attacks of predators. No local parasite has been recorded in Mauritius.

Six species of Trypetids are recorded. Of these, the flies attacking cucurbitaceous fruits are the most harmful. Experiments with numerous attractants for fruit-flies are mentioned. The only bait showing any success in the control of the Dacus flies is the Mally fruit-fly bait. Parasites have been imported from South Africa and Ceylon without success. Further attempts should be made.

The bionomics and breeding places of the blood-sucking fly, Stomoxys nigra, are described.

The Red Ant, Solenopsis geminata, is a major pest of seedlings in Mauritius. It is now destroyed by the use of a diesel-clay emulsion. Baits containing thallium sulphate have been tried without success.

The rôle of the Black Ant, Technomyrmex detorquens, in preventing development of the Coccinellid predators on Icerya seychellarum is emphasised. Barber's poisoned bait has been found very useful against this household pest.

A review of the species of termites found in Mauritius as well as the various means of control used against them are given. An insecticidal powder containing arsenious oxide has given the best results.

During the last 25–30 years, 64 species of parasites and predators have been imported for the biological control of eight species of insects of major economic importance and of two species of noxious plants.

The results achieved indicate that the introduction of parasites and predators in insular countries like Mauritius should be carried out only after a thorough investigation of the various ecological, biotic and climatic factors existing between the country of exportation and the country of importation.

The rôle of cyclonic disturbance in the fluctuation of the parasite population is mentioned. Scoliid parasites, for instance, are generally scarce after violently disturbed weather and may sometimes remain so for two or three years after the disturbance.

1. The work here reported was carried out in Bwamba County, Uganda, a district where human yellow fever has recently occurred. It consisted of continuous 24–hour catches of biting mosquitoes in a banana plantation, made simultaneously at ground level, 6 ft., 12 ft. and 18 ft.

2. Aédes (Stegomyia) simpsoni, Theo., the carrier of human yellow fever in Bwamba, was found to be active throughout the day at all these levels.

3. The presence of sylvan mosquitoes in the banana plantation was noted. The nearest forest was ½ mile away.

4. The biting cycle of the strictly diurnal A. simpsoni was studied, and it was found that this species was most active on warm cloudy days. The main factors decreasing its activity appeared to be cold, wind, and direct hot sunshine.

In the subgenus Mochthogenes, only the pupa of Culex (M.) inconspicuosus, Theo., has been described. Since one of us (M.P) has obtained the immature stages of all the known species, including C.(M.) castor, De M., we take advantage of this opportunity to give a key to the pupae. The pelts were all obtained from specimens bred in isolation at Yangambi, Belgian Congo, and the resulting adults identified by means of the male terminalia.

1. The danger of the establishment of yellow fever in certain of the forests of Kenya is pointed out. Kenya has had two recognised cases of the disease in recent years.

2. The Kaimosi forest was selected as a suitable area for investigation and the general environmental conditions are described.

3. A mosquito survey was undertaken over a period of two years and particular attention was paid to the question of “acrodendrophily” i.e., the preference shown by certain species of mosquitos for life in the tree-tops.

4. Five species of mosquitos—Culex nebulosus, Aëdes capensis, A. fraseri, A. deboeri subsp. demeilloni and A. longipalpis breed in high tree-holes; the last, almost entirely so. The many characteristically low breeders include A. aegypti and A. africanus. There is an interesting distinction between the two commoner Megarhines; M. brevipalpis breeds high, M. barbipes, low.

5. Four species of mosquitos—A. apicoargenteus, A. fraseri, A. africanus and A. longipalpis were found biting in the tree-tops; the last two being rare in ground catches.

6. Forest with a broken canopy proved best for adult catching and the morning was a better time than the (usually overcast) afternoon. Night searches gave negative results. Catches on high tree platforms appeared to be more prolific than those oa the ground.

7. The following points of special interest in regard to individual species of mosquitos are summarised below: —

(i) Megarhine larvae consume about 20 fourth-stage aegypti larvae a night. Pupal stage lasts on an average for nine days.

(ii) Aëdes aegypti breeds commonly in two sites (a) recently felled trees at forest edge; (b) rock pools in rivers in drought periods. Larvae are found a mile or more inside the forest. Breeding of this species has been discovered as high as 6,500 feet.

(iii) Aëdes apicoargenteus was the commonest adult. Some specimens survived 55 days in captivity.

(iv) Aëdes africanus shows a seasonal incidence, being commonest at the end of the “long rains”. Its favoured breeding places are the buttresses of the tree, Craibia elliottii.

(v) In the larval stage, Aëdes capensis is the commonest mosquito.

(vi) The characteristic breeding place of Theobaldia fraseri contained 79 parts of oxidisable matter per 100,000 of water.

8. Probably at least two trees per acre have rot holes with larvae and about 14 per cent, of the Dracaena plants are infested. Holes in shaded granite boulders are another common source of sylvan mosquitos.

9. Surveys of adjacent forest areas at different altitudes revealed striking changes in the mosquito fauna. Aëdes pulchrithorax is the prevalent species at the 6,500 foot level; A. kapretwae at the 8,500 foot; whilst in general, A. africanus, A. aegypti and A. bambusae appear to be widespread.

10. A study of the lists of mammals, trees and mosquitos indicates that the relict forest of Kaimosi contains numerous “western” species which are not found elsewhere so far to the east.

11. Immunity tests performed at the Yellow Fever Research Institute, Entebbe, demonstrated the absence of yellow fever in man and monkeys at Kaimosi. The monkeys show, however, immunity to Semliki forest virus and either Japanese B or St. Louis encephalitis virus.

12. The human inhabitants suffer from malaria and onchocerciasis (the latter carried by Simulium neavei) and the monkeys and fruit bats are infected with species of Plasmodium.

13. The Kaimosi forest from every standpoint (including meteorological) is suitable for the establishment of jungle yellow fever and possible measures of control ate briefly suggested.

14. Short descriptions of new species, etc., of mosquitos are given in the Appendix

A new mealybug injurious to cacao in the Gold Coast was described by Laing in 1944 under the name of Pseudococcus exitiabilis (Bull. ent. Res., 35, p. 91). It was said that it had been reported by the collector, Mr. H. E. Box, to be one of the Coccid vectors of the “Swollen Shoot” virus disease of Cacao. This was later confirmed by Box (Nature, 155, 1945, p. 608).

The eggs of A. gambiae var. melas are distinctly different from those of typical gambiae, and it is now regarded as a distinct species, A. melas. Other workers have found that the larvae also differ, physiologically and structurally. All adults with an extra dark band on the palps—4-banded forms— are known to be melas, but those adults with normal 3-banded palps can so far only be distinguished from typical gambiae by egg characters.

A. melas is now known to be an important vector of malaria in coastal districts in West Africa. In some estuarine and mangrove swamp areas it may be even more important than typical gambiae. In melas caught in Freetown estuary (mostly from Wellington village), 42 out of 1,000 glands dissected were positive, giving a sporozoite rate of 4·2 per cent. for all months of the year. The oocyst rate was 4·7 per cent., and the total infection rate was 7·8 per cent.

In Freetown estuary melas is rare in Freetown itself, and in the adjoining village of Kissy, but in all other parts of the estuary is at least as important as typical gambiae. In many places it is the dominant vector. In Wellington to the east of Kissy, and on the Bullom shore which forms the north shore of the estuary, melas forms about 90 per cent. of Anophelines caught in houses.

(1) The methods of breeding larvae of Capnodis are described.

(2) A description of the larva and of its methods of locomotion is given.

(3) A study of the reaction of the larva to external stimuli is presented. It is pointed out that phototropic or geotropic reactions have no influence on the activity of the larva and that it is guided to its food through stereotactic and chemotropic reactions.

(4) The larva can detect roots or twigs from a distance of about 40 cm., and it can distinguish between the odour of various plants.

(5) Of various fruit trees, the odour of stone fruit was most attractive, and of these, almond comes first and apricots second.

(6) After the larva has located the root, and moulted, the sense of smell weakens gradually until it disappears. A comparative morphological examination of the antennae of neonate and mature larvae shows the olfactory organs are not present in the latter, while distinctly developed in the former.

(7) The larva feeds on the bark, tearing off minute particles, which it chews and finally discards.

(8) The tearing off of the fibres is facilitated by a fluid secreted from the mouth of the larva which softens the wood.

(9) Physiological tests show this fluid to contain a cellulose, a pectinase and an amylase.

(10) Development from hatching to pupation at 33° C. lasts about 60 days, at 27° C. about 100 days.

(11) From empiric data it is apparent that the threshold of development is about 18° C.

(12) From measurements and calculations according to the law of Dyar, the larva must moult at least nine times before pupating.

(13) The larvae resist temperatures above 42° C. for eight hours, but die after a few days in such temperatures.

(14) Practical considerations for the fruit grower based upon this study are presented.

The sandflies of Cyprus have been examined. The following ten species were found: P. papatasii, P. perniciosus var. tobbi, P. chinensis (a local race), P. perfiliewi (rare), P. sergenti, P. alexandri, P. larroussei (rare), P. fallax cypriotica, var. n., P. azizi, sp. n., and P. parroti.

Melanic forms of P. parroti were found. Melanism was associated with a reduction in the teeth of the pharynx in the female in the few specimens collected.

The race of P. chinensis found on the island differs from those hitherto described.

The general composition of the sandfly population of Cyprus is different from that of any other part of the Mediterranean examined.

P. major which is common in Palestine, Syria and the Balkans was not found.

Canine kala-azar is common on the island. P. perniciosus var. tobbi and a race of P. chinensis should be considered as possible carriers but this point must be determined experimentally.

In February, 1944, No. 2 Entomological Field Unit, R.A.M.C., arrived in India with the first consignment of DDT (dichlor-diphenyl-trichlorethane) to be used there for research purpose. Experimemts to determine the larvicidal effects of this substance were carried out by the unit, of which I was Commanding Officer.

Ferrière (1941) in his study of the Euplectrini (Chalcidoidea, Eulophidae) has described three yellow species from Ceylon, all parasites of nettle grubs (Limacodidae) from tea, and has erected three genera to accommodate them. They are Neoplectrus maculatus (1940), Platyplectrus natadae (1941), and Metaplectrus thoseae (1941). In April, 1944, the writer obtained two females from Thosea cervina, and at first sight they were thought to be Metaplectrus thoseae, but closer examination showed them to differ from Ferrière's description in several important respects. In order to ascertain their systematic position the following brief study of Ceylon specimens was under taken.

Since the recognition by Bolivar (1912) of Hieroglyphus nigrorepletus as a distinct species, Coleman's (1914) note and Uvarov's (1922) valuable revision of the rice grasshoppers, it has been clear that in the earlier literature this species has been confused with H. banian, F., chiefly under the name of H. furcifer, Serv., while H. bettoni, Kirby, 1914, and H. vastator, Carl. 1916, are synonyms.

The theory of phases, Uvarov (1921), had the object of explaining the interrelationship between different forms of Locusta migratoria and Locustana pardalina. This theory has been accepted by most entomologists working on locust problems. Authors such as Faure (1923 and 1932), Johnston and Maxwell-Darling (1931) and later a series of others including Hussein and Ramchandra Rao, proved and confirmed the truth of Uvarov's theory.