This paper deals with seven Indian species and one African variety belonging to the subfamilies Spathiinae and Doryctinae. Four of the species are important parasites of the cotton stem weevil, Pempheres affinis, Fst., and are described as new in compliance with an urgent request for their names.

As cotton crops in many parts of the world end either with the onset of winter or of the dry season, it is natural that the larval diapause which becomes more and more conspicuous as the crop ripens should have come to be regarded as an instance of either hibernation or aestivation; yet in the West Indies where the following observations were made, there is no winter, nor does the ripe boll phase of the crop necessarily fall in the dry season. The latter moreover is not one of complete drought but rather dry only by comparison. Indeed in some islands, such as Montserrat and St. Kitts, the crop is harvested in the wet season. Yet long-cycle or resting larvae are regularly found in all of these islands.

In Nyasaland, as indeed in most territories in East Africa, the greatest single factor governing the distribution of both human population and stock is the presence of tsetse fly. Exact records, therefore, of the distribution of this fly are of importance. In the present article an attempt is made to summarise the present state of our knowledge regarding the prevalence of Glossina in the North Nyasa district.

The Ephialtes which have been bred from the codling moth, Cydia pomonella, L., have usually been determined as Ephialtes (Calliephialtes) extensor, Taschenberg 1863. Two species have been confused under this name, and neither of them is E. extensor, which, from the description and from material examined in the Brauns and Thomson collections, is a synonym of Ephialtes punctulata, Ratzeburg (═Pimpla punctulata, Ratz. 1844) (syn. nov.). The type of the latter species has been examined, as have the types of Ephialtes caudata, Ratzeburg 1848, and E. crassiseta, Thomson 1877, which are the two species that were actually bred from the codling moth. These species may be readily distinguished by the relative lengths of the segments of the hind tarsi and also in the female by the form of the ovipositor. The following key distinguishes the three species mentioned above.

These keys and illustrations have been prepared in response to many requests. They concern only those species of Anopheles which have been recorded as occurring in West Africa south of the Sahara Desert as far as the equator. Much of the material has been derived from the recent Monograph by the late Dr. A. M. Evans on the Anophelines of the Ethiopian Region published by the British Museum in 1938. Personal acquaintance with the Anophelines of East and South Africa and examination of the specimens in the collection of the Department of Entomology of the London School of Hygiene and Tropical Medicine have assisted in the preparation of the keys.

The following is an account of the continuation of experiments and observations carried out in connexion with an investigation into the ecology and control of pine beetles, with special reference to Myelophilus piniperda and M. minor.

1. The female tsetse extrudes her larva on soils ranging from fairly heavy clay to coarse sand; the presence or absence of organic matter seems to be immaterial.

2. The soil temperature varies greatly in different breeding-grounds in the dry season, but little in the rains.

3. The soil water content varies greatly in different breeding-grounds in the rains, but little in the dry season.

4. The soil water content in some of the breeding-grounds falls so low in the dry season that there can be no doubt that the atmosphere in these soils is below saturation.

5. Evaporation measured at 5 inches above ground-level varies little from site to site; bigger and important differences occur at greater heights above the ground where the screening effects of thicket become operative.

6. The seasonal changes are so great at Gadau that no one breeding-ground can satisfy the female's requirements throughout the year; instead, different breeding-places are selected for different seasons.

7. The cycle for G. morsitans is as follows: In the rains breeding occurs under palm fronds and logs in the open woodland. In the early dry season breeding continues in the open woodland, but shifts from the palm and log sites to the small thickets; breeding also starts in the more open parts of the forest islands. At the beginning of the very hot weather all the thickets of the open woodland are evacuated, and breeding is confined to the densest parts of the forest islands. In the early rains the movement is reversed: breeding shifts out into the open woodland, and in the heavy rains is confined to the log and palm sites.

This cycle fits in closely with the cycle for the seasonal concentration and dispersal of the adult population (Nash 1937, pp. 85–90).

8. The major wet season breeding-ground of G. tachinoides is unknown, but the cycle is believed to be as follows: In the early dry season breeding shifts from the log, palm, and probably from the unknown site, to the small thickets and forest islands, and becomes maximal in the cold season. Breeding now decreases in all sites, suggesting that none is really suitable—a surmise which is strengthened when tremendous breeding activity starts in the river-bed, as soon as it becomes available at the beginning of the hot season. In the early rains this site is destroyed and breeding is believed to commence in the unknown site, as it certainly does under the logs and palms.

1. The thermal constant and the zero of the velocity curve have been determined for each of the pre-adult stages of Tortrix postvittana, Walk. The experimental methods are described. The thermal constant for the eggs is 153 day degrees C. and the zero of the velocity curve 4·80°C. The corresponding constants for the larvae are 469 day degrees C. and 8·05°C, and for the pupae 182 day degrees C. and 5·93°C.

2. The experimentally determined constants and the mean monthly temperatures have been used to calculate the peak of the flight period of the adult moths at Huonville, Tasmania, during the 1935, 1936 and 1937 seasons. In three cases out of four the calculated dates approximate very closely to the observed dates for the peak of the flight period.

3. The results of observations on the number, duration and head-widths of the larval instars are given. The majority of larvae fed on young apple leaves had four instars. A greater proportion of the larvae fed on mature apple leaves had more than four instars. The length of larval life at 25°C. is significantly longer for both male and female larvae when they are fed on mature leaves. The head width of the final instar of four-instar female larvae is significantly greater than that of the final instar of four-instar male larvae. Food quality has no apparent influence on the head width of the final instar of either male or female larvae.

4. At 25°C. the length of larval life of female larvae is significantly longer than that of male larvae when both are fed on the same food ; the same tendency is exhibited at other temperatures. The separate velocity curves for male and female larvae are not significantly different in slope. The difference between velocity values for male and female larvae at the mean temperature approaches significance.

5. Larval mortality increases rapidly at temperatures above 30°C. and 100 per cent, mortality occurs at 35°C. Starved larvae at low temperatures and high humidities show a tendency for the survival time to increase with the size of the larvae. Final instar larvae under these conditions can survive for two and a half months.

The Chalcidoidea mentioned in this paper are mostly parasites of the cotton stem-weevil, Pempheres affinis, Fst., in South India. They were bred by Mr. P. N. Krishna Ayyar during the years 1935 to 1938 and were sent in various collections to the Imperial Institute of Entomology for study. Another species, parasite of the Coconut Hispid, Promecotheca papuana, Csiki (antiqua, Ws.), has been added here, its description having been required for biological studies.

The object of the present paper is to describe the results of some cage experiments with Zonocerus variegatus, L., carried out at Ibadan between March 1932 and December 1937.

The cages used for the breeding experiments were about 2-05 metres in height and were filled with soil to a depth of about 51 cm. The upper part of each cage was made of wire gauze and had a cubic capacity of about 1-43 cubic metres (154 cm. high by 102 cm. by 91 cm.). The grasshoppers were fed on the leaves of sweet cassava (Manihot utiHssima) and water was sprinkled on the food.

Methods for the quantitative survey of the incidence of Heliothis armigera have been in continuous operation in the Barberton area of the Eastern Transvaal from 1929 to the present; since 1933 the Survey was operated similarly in Swaziland and Northern Natal.

It was accepted early that the bollworm situation in cotton, which primarily it was desired to ameliorate, depends largely upon the influences exerted by other food-crops of the insect grown prior to and in association with cotton, and the investigations were instituted with a view to acquiring the fullest information on the incidence, habits and reactions of H. armigera with respect to the chain of cultivated and natural food-plant situations existing under differing climatic conditions in the course of the year.

The present paper is the first of a series communicating the results of investigations which proceed in various directions from information supplied by the Cotton Pest Survey centred upon Barberton. The paper deals with the annual course of bollworm incidence as indicated, in the first instance, by egg counts taken twice-weekly, year by year, in examples of all food-plant situations according to methods of sampling and calculation devised here.

The wheat crops in certain districts of England are attacked every year by the wheat-stem sawfly, which in its turn acts as host to various species of parasitic insects. The aim of the present investigation is to try to discover from an analysis of records if any sort of simple numerical relations exist within the complex including the wheat field, the sawflies which infest the wheat-stalks, and the parasites which attack the sawflies. The results of this work lead to a discussion of the peculiar difficulties involved in the application of mathematics to the study of animals and plants in their natural environments.

In preparing the part dealing with the Diprionidae in a synopsis of the British sawflies I came upon several morphological characters that, if used or made more use of, would greatly facilitate the naming and classification of this economically important group of insects. A comparison between Neodiprion and Diprion (s.l.) revealed at once striking differences in the shape of the meso-scutellum, the sculpture of the abdomen and the anal cell in the hindwing, characters easily visible in the field and therefore of great importance to the economic entomologist. Diprion pini, L., and similis, Hartig, were found to differ from the other Diprion species, among other things, in their small cenchri, a character easily visible in the field, and the genus has been divided.

The new species described herein was found, in the first instance, on cacao (Theobroma cacao, L.) at the Central Experiment Station, Serdang, Selangor, Federated Malay States. Later on, a few specimens were caught on the leaves of annatto (Bixa orellana, L.) plants situated at about two hundred yards from the area planted with cacao.