In our investigations on Smynthurus viridis, L., a study has been made of the population of this species, in an area of lucerne, at intervals of three and four days throughout the season.

The density of the population of the species in a favourable pasture is markedly affected by the relative abundance of certain food-plants, especially leguminous species and particularly clovers such as subterranean clover (Trifolium subterraneum) and lucerne (Medicago sativa).

The activity of the insect is intimately associated with the moisture of its environment, and the moisture content of the surface soil is one of the most important factors affecting the environmental conditions.

Considering the habits of the insect, it was felt that the sweeping method would not give a reliable record of the total population in a given area of pasture. A sample obtained by sweeping with a net does not include individuals on or near to the surface of the soil. The relative proportion of individuals situated on or near the soil surface and those situated further up the plants varies considerably from time to time, according to the meteorological conditions, the growth of the herbage and the moisture content of the surface soil. It was necessary therefore to devise a simple method by means of which a more accurate record of the total population in a given area could be obtained.

1. This report continues the account of the experimental field work carried out by the Tsetse Investigation in Northern Nigeria from May 1926 up to the end of 1929. G. morsitans and G. tachinoides are the tsetse concerned. The main object of this work was to attempt to control tsetse by the destruction of primary and secondary foci by the clearing of all fringing forest, the general woodland being left untouched. Two main experimental areas have been dealt with, the Sherifuri area described previously and the Matyoro experimental area.

2. Methods of clearing and dealing with re-growth are described in detail. Records show that re-growth although very rapid the first year, then slows down to such an extent that it may not be economical to re-slash more often than every third year. The effect of clearing on tsetse was controlled by collecting fly week by week from certain fixed foci. These flies were dissected and the following factors noted : the sex proportion in the catch, the rate of catching, the state of nutrition, the proportion of very young flies, the blood content of the gut with classification of the kinds of blood found, and the trypanosome infection.

With G. morsitans, clearing of fringing forest only up to 800 yards from the collecting centre had no apparent effect on the wet season extension but at four miles it was reduced to one-sixth of its old figure.

The following is a summary of some experiments that were carried out in 1930, 1931 and 1932 on the sandy soils of Darnitza Forest Reserve (near Kiev) and Kruilov Forest Reserve (near Kremenchug), 112 plots, each covering an area of 100 square sazhen (70ft. by 70ft), having been used for the tests. The polychlorides were of two kinds: dark polychlorides, which had a less homogeneous structure and contained a smaller quantity of dichlorides, the amount of higher polychlorides being greater; and light-coloured polychlorides, which chiefly contained dichlorobenzenes and only relatively small quantities of chlorobenzene and higher polychlorides. In the experiments during 1931 and 1932 certain quantities of the chemical were applied to a given area, namely: 26,047 gm., 15,935 gm. and 13,026 gm. to an experimental plot of the size mentioned above. The chemicals were introduced into the soil at intervals of 28, 21 or 14 inches, the lines of the holes being also 28, 21 or 14 inches apart respectively.

This paper deals with a number of collections of African sandflies sent for identification by the Imperial Institute of Entomology and by Dr. P. A. Buxton of the London School of Hygiene and Tropical Medicine. I have to thank Prof. S. Adler for putting some of this material at my disposal.

L. sericata, L. cuprina, Ch. rufifacies, C. stygia and C. augur have been bred through many generations in captivity. These flies were bred in artificial light as well as in sunlight. Inbreeding had no effect upon activity, fecundity or length of life.

A diet of protein is necessary for the maturation of ova but not of spermatozoa.

Oviposition is not strictly associated with a suitable larval environment, but is more in the nature of a response to a tactile stimulus. Copulation appears to provide an essential stimulus for oviposition.

No evidence of parthenogenesis has been obtained and unfertilised females did not lay eggs.

The maximum oviposition observed was 3,171 ova by a hybrid Lucilia. This fly lived 94 days.

A total oviposition of 2,373 ova was observed in a L. sericata. Both parent flies lived 77 days.

The number of ova a fly can produce at one time is dependent on its size and thus on the amount of food obtained in the larval stage.

The sex-ratio for Lucilia is very close to 1 : 1. Starvation in the larval period did not have a marked effect on the sex-ratio.

It is possible to cross the two closely related species of Lucilia, and the cuprina characters appear to be dominant. It is unlikely that this cross occurs in the field.

The Solomon Islands lie to the east of New Guinea and consist of an archipelago a thousand miles in length and about half this distance in breadth. They are divided politically into the Northern Solomons (formerly German but now administered under Mandate by Australia), and the British Solomon Islands Protectorate. This latter lies roughly between five and twelve degrees south of the equator and is believed to have been united both to New Guinea and Australia from at least the Triassic to the early Tertiary. As there is now a deep sea between the archipelago and the two land-masses, the former falls into the ancient section of the continental islands of Wallace.

The rainfall averages 150 inches, the maximum shade temperature has a mean of 90°F., and the relative atmospheric humidity averages 92 per cent.

The Group consists of six large islands ranging from 60 to 120 miles in length and many smaller ones, including the isolated Santa Cruz group to the east. The main islands are composed of both coralline and volcanic (chiefly diorite) rocks and hence exhibit a wide range of soil-types from coralline sands and red clay to alluvium. Evidence of former extensive elevation is provided in raised coral-beaches. The islands are generally covered with jungle and densely wooded to their summits which rise in places to over 8,000 feet. An exception to this is the central and western portions of the northern coast of Guadalcanal, which consist of grass plains and undulating downland.

Towards the end of 1931 a study of the eggs of Anopheles mosquitos was commenced, primarily with a view to establishing any characters in the egg which may prove useful in differentiating closely allied species, and in particular those suspected of being concerned in the transmission of malaria.

The eggs of ten species of Anopheles are described and figured below : mauritianus var. ziemanni, Grünb., implexus, Theo., pharoensis, Theo., theileri var. hancocki, Edw., christyi, N. & C., gambiae, Giles (costalis, Theo.), transvaalensis, Carter, funestus, Giles, marshalli, Theo., and moucheti, Evans. Of these the writer has had the opportunity of examining specimens of Anopheles gambiae and funestus from four different regions in Uganda, namely, Kampala (3,900 ft.), Jinja (3,800 ft.), Mbale (4,000 ft.) and Fort Portal (5,100 ft.), and no local variations were observed. The eggs of two species dealt with in this paper have been previously figured by workers in other parts of the world. Edwards (1921) reproduced a drawing by Patton of the eggs of Anopheles gambiae (costalis) from Arabia, and Theodor (1924) published a drawing of those of A. pharoensis from Palestine. Both illustrations show eggs which in general structure are very similar to those of the same species in Uganda ; the sculpture of the membrane is not figured. Individual variation within the eggs of a single adult was found to be constant in the case of A. marshalli, the three forms figured being represented in each of the three batches examined.

The Australian sheep “ blowfly ” Chrysomyia rufifacies, Macq., is shown by a study of chaetotaxy and the genitalia to be distinct from C. albiceps with which it has been considered identical. A discussion is given of the composite genus Chrysomyia and the genera into which Séguy has recently divided it. The synonymy of C. rufifacies is given and also the distribution of C. rufifacies, C. albiceps and C. putoria, the three species which Patton has considered synonymous.

Methods of breeding and manipulating Aëdes aegypti are described. Experiments on length of life were carried out with 534 mosquitos under eleven sets of conditions of atmospheric temperature and humidity. Also, 379 females were given an opportunity to suck blood under 11 sets of conditions. The following conclusions were reached :—

1. The length of life of starved mosquitos at 23°C. is very much dependent on humidity, but it cannot be directly related to saturation deficiency.

2. In these experiments there is no significant difference between the mean survivals of males and females, the former being generally longer.

3. The survival periods of fed and unfed females have a similar relation to humidity, the fed ones surviving the conditions for a longer period, irrespective of the date of feeding.

4. The effect of a change of temperature of 7°C. on the survival at 23°C. and 30°C. is much less than would be expected when the long survival period at 10°C. is considered.

5. In the absence of any efficient physiological adaptation for retarding loss of water, the females, possibly for this reason, seek a blood meal mainly in saturated air at the temperature of maximum activity.

Twenty-one collections of larvae and pupae from Bromeliads, growing in trees or on the ground, were made in São Salvador, the capital of the State of Bahia, Brazil. Four species of Microculex and one Sabethine were bred out. Of these, one new species and certain new forms are described. The new species is called Culex (Microculex) davisi in honour of Dr. Nelson C. Davis, at whose suggestion this study was first undertaken. Since no Aëdes (Stegomyia) aegypti were found, it would appear that Bromeliad breeding is probably of no importance from the standpoint of a yellow fever control campaign in this region.

The study of Dipterous insects in Kenya Colony has been restricted, to a large extent, to the Culicidae and their relation to malaria, and to the Tabanidae and the genus Glossina in connection with trypanosomiasis, the non-bloodsucking Diptera having received but little consideration.

“ Blowflies ” or “ maggot-flies ” are by no means uncommon in the Colony, and evidences of myiasis in its various forms are numerous. Symes & Roberts (1932) cite instances of the larvae of Sarcophaga haemorrhoidalis and of Lucilia sericata in the exposed brain substance of a woman ; and of Chrysomyia bezziana in an ulcer on the foot. Cordylobia anthropophaga, parasitic in the skin of man and other animals, is common, and Auchmeromyia luteola (in reality a blood-sucker in its larval stage) is distributed from the coast to the southern boundary of Abyssinia. The “ sheep nasal fly ” is extremely abundant, and many other larvae of Oestrus species have been recorded from game in the Colony.

Wounds, ulcers and sores in natives and in animals are often infested with maggots. I have seen, on several occasions, maggots in the ears, and in sores under the eyes, of native children, and in leg-wounds of native labourers. Still more frequently have I observed maggots in wounds of animals ; they occur at the bases of distorted, and in the scars of broken, horns, in the lesions caused by tick-bites, in injured eyes, and in the soiled fleece of sheep. Animals on the point of death are often attended by myriads of sarcophagous flies, the vast numbers of Chrysomyia marginalis in particular presenting an extraordinary sight.

(1) The history of Otiorrhynchus cribricollis in Australia is traced and records of its distribution in other countries are cited.

(2) Methods used in the experiments are described.

(3) The incubation period of the egg was found to vary between 14 and 37 days. The average was 22·3 days.

(4) The habits of the larva are described. Dyar's Law was applied to determine the number of instars, which was found to be 10.

(5) The normal duration of larval life is from May to October or a period of about 5 months.

(6) About 10 per cent. of the larvae aestivate through one summer. These have a larval life of about 17 months.

(7) Normal life of the adult is from November to April, about 5 months, but some (about 11 per cent.) hibernate through one winter and thus live 17 months.

(8) The adults feed in two seasonal periods separated by an interval of about 6 weeks, during which time they are inactive.

(9) The adults have been observed to feed upon 21 different plants, representing 12 different families.

(10) Most of the eggs are laid in the autumn, but a few are laid in the spring.

This paper consists of a preliminary report on investigations of the parasites of Coleophora laricella in Europe, with a view to their possible utilisation in Canada.

Systematic and biological notes on the more important species are given.

The most promising parasite, Angitia nana, has already been shipped to Canada. It is a solitary internal parasite of the case-bearer larva. Further investigations are necessary before it can be considered safe to introduce any other species.

I am very grateful to Dr. C. Ferrière, of the Imperial Institute of Entomology, for the time and trouble he has given to the work of identifying the parasite material. The late Mr. J. C. Robbins helped materially by kindly carrying on observations while I was absent through illness, and by collecting material in the field. Mr. R. J. Spittle has been of great assistance in the production of the finished drawings, several of them being mainly his own work. A number of the earlier field collections were made by Mr. H. S. Hanson.

1. The biology and larval morphology of three Alysiine Braconids and one Chalcid, parasites of the pre-imaginal stages of some carrion-infesting Dipterous larvae, are described.

2. The mode of hibernation of the parasites is recorded.

3. The oviposition of Alysia manducator and Aphaereta minuta is discussed in detail, attention being drawn to the hitherto neglected sense-organs located in the tarsi of these two species and to their importance in the process of oviposition.

4. The differing responses of full-grown Lucilia sericata larvae to parasitism by Alysia manducator at high and low temperatures are suggested to be due to differences in the physiological states of the host larvae at these temperatures.

5. A comparative study of the three endoparasitic Alysiines suggests that Alysia manducator may have reached a state of endoparasitic life relatively later than the other species studied, or at least has not yet reached such an advanced stage of endoparasitic specialisation as have Aphaereta minuta and Aspilota nervosa.

6. The growth of the egg in Aphaereta minuta and Alysia manducator and of the larvae of Mormoniella vitripennis is discussed.

1. Methods used in the production of pupae of G. morsitans, Westw., in the laboratory have been described.

2. Observations, based on the pupae produced in the laboratory, have been recorded on larviposition, pupation, pupal period and stages of pupal development.

3. The pupal period was found to vary with the temperature, from 23·1 days when kept constantly at 86°F., to 48·5 days at a varying temperature, the mean noon temperature during development being 70·0°F.

4. Examination of puparia collected from natural breeding-sites showed that there is a fairly heavy mortality in the pupal stages in nature, amounting in some cases to as much as 50%.

5. Parasitisation by the Hymenopterous parasite, Syntomosphyrum glossinae, was found to a very slight degree—0·2& only.

6. Heavier parasitisation by three species of Bombyliids—Thyridanthrax abruptus, T. lineus, and T. argentifrons—occurred.

7. The living, dead, and parasitised puparia could be distinguished by (a) immersion in methylated spirit of S.G. 0·820, when those sinking would be alive, and (b) subsequent immersion in petrol of those floating in methylated spirit, when those sinking would for the greater part be parasitised and those floating would be dead.

8. The degree of temperature lethal to pupae was found to depend on duration of exposure. Thus, whereas pupae survived exposure to 55–57°C. for 2 minutes, 45–50°C. was lethal when the exposure lasted half an hour, whilst even 40°C. was lethal when continued for 4 hours or more, and pupae failed to survive 13 days at 35°C.

In the spring of 1932 the President of the International Locust Office at Damascus invited me to visit the main breeding areas of the Moroccan Locust (Dociostaurus maroccanus, Thunbg.) within the territories of the states adhering to that Office, i.e. Turkey, Syria and Iraq, in order to survey the local locust problem and to advise on the best general policy of locust control. The visit represented partly a continuation of the previous season's work in Western Anatolia (Uvarov, 1932) and concerned the great locust area which comprises the south-eastern vilayets of the Turkish Republic, the northern provinces of Syria and northern Iraq.

The voyage was planned to take place at the period when oviposition by locusts usually occurs, and about three weeks in the second half of May and early June were spent in actually touring the areas subject to regular locust invasions in Iraq and Syria. Unfortunately, no arrangements were made for including Southern Turkey in the tour and, therefore, an important section of the area remained unstudied.

While the choice of the period for the ecological investigations proved to be correct, the year was scarcely favourable for reaching very definite conclusions. Locust swarms were numerous and rather widely spread during at least two or three previous years, but the meteorological conditions of the early spring of 1932 were quite exceptional, owing to the practical absence of rains, which caused great mortality amongst young hoppers.