The species of Sesiidae reared from larvae feeding in the vines and tubers of sweet potato (Ipomoea batatas) in Kenya are described as new and named Synanthedon leptosceles and S. dasysceles, respectively. Illustrations are given of the adults and male and female genitalia of both species. S. leptosceles is differentiated from the superficially similar East African species S. erythromma Hmps., which also is associated with sweet potato. Aegeria pyrostoma Meyr. is synonymised under S. erythromma following the examination of type material. S. dasysceles is noted to be readily distinguishable from these and other known species of Synanthedon by the rough scaling and white markings of the legs.

The natural moth emergence-pattern of Diparopsis castanea Hmps. from non-diapause and diapause pupae is described for Malawi and Rhodesia and related to the growth of the cotton plant. Pupal populations and mortality in the field are assessed and the location of pupae in the soil for both ridged and flat land is determined. The effect of temperature on the development of diapause pupae is investigated. Temperatures both above and below 75°F. are shown to cause inhibition of pupal development. The investigations show that it is possible to effect a major alteration in the period of moth emergence from diapause pupae by burying the pupae to a depth of eight inches and thus avoiding heat inhibition. In this way, the majorrity of moths emerge before the cotton crop is able to support an infestation. Attempts to achieve this effect with a natural field population of pupae failed and further investigation is required. Heavy grass mulches are shown to inhibit pupal development possibly throgh reduction in soil temperature and retention of soil moisture.

The size and occurrence of the first brood of adults of Aeneolamia varia saccharina (Dist.) are examined in relation to the pattern of egg eclosion and rainfall. The proportion of eggs hatching within a month of oviposition in the laboratory (short-period eggs) decreased from over 90% in August to less than 20% in January, but the incubation periods of the remaining, long-period eggs were longest in those laid during October and November. The overall hatching distributions tended to be bimodal with most eggs hatching during the early months of the year under moist conditions at 26°C. Dry soil conditions delay eclosion, and eggs obtained from fields during the dry season and then incubated under moist conditions tended to hatch at the normally expected time of the first rains in May. The numbers of eggs expected to produce the first brood, computed from laboratory hatching data and estimates of the numbers and fecundities of froghoppers during the second, third and fourth broods, were less than the actual numbers sampled just before the first rains. There was a close relationship between the first rainfall of over one inch within 48 h and adult emergence 27 and 34 days later, and 85% of field egg populations in May had hatched and/or died by the week after the first rains. However some variation in the date of their occurrence accounted for non-synchrony of first broods over the region. The numbers of diapause eggs in fields sampled during the dry season failed to give a good predictive relationship with first brood adult populations, probably because of density dependent mortality of eggs or hatchling nymphs.

Egg cannibalism serves various functions in the Coccinellidae. Here we examined the fitness consequences of egg cannibalism by neonates, fourth instar larvae, and prereproductive adults of Coleomegilla maculata DeGeer, with beetles fed a diet of Ephestia kuehniella Zeller eggs. Cannibalism of two eggs by neonates had no effect on development, and cannibalism of five eggs by fourth instars did not benefit any aspect of reproduction, but delayed pupation slightly. Cannibalism of eggs by pre-reproductive adults had no effect on reproductive success in any combination of reciprocal crosses of cannibals and non-cannibals. Females did not recognize, nor avoid consuming, their own clutches, and cannibalism propensity did not change following mating and onset of oviposition in either sex. These results contrast with those for more strictly aphidophagous species in which larvae gain developmental benefits, and females may recognize and avoid filial egg clusters while using cannibalism to interfere with conspecific females, whereas males reduce egg cannibalism after mating because they cannot recognize filial clusters. Egg cannibalism may confer developmental benefits to C. maculata when diet is suboptimal, as previously shown, but no such benefits were evident on the high-quality E. kuehniella egg diet. Female C. maculata do not require aphids to reproduce and distribute their eggs broadly in the environment, given that larvae can develop on pollen and non-aphid prey. Thus, C. maculata is not subject to the intraspecific competition that selects for cannibalism in more aphidophagous species, and also lacks many secondary adaptations associated with the behaviour.

The genus Dociostaurus, Fieb., which is synonymous with Stauronotus, Fisch., includes several species of locusts and grasshoppers injurious to agriculture in South-Eastern Europe, Central and Western Asia and North Africa, the well known Moroccan locust (Dociostaurus maroccanus, Thunb.) being one of the worst pests in Algeria, Tunisia, Asia Minor, the Caucasus and Turkestan. The systematics of the species of this genus are in a very unsatisfactory state, and this, together with the tendency of the species to individual variability, is the cause of many mistakes in their identification on the part of economic entomologists. The object of this paper is, therefore, to establish a more or less natural system of the species enabling everyone to identify them with certainty.

The biology of the immature stages and adult eclosion of Ufens principalis Owen, an important parasitoid of Homalodisca eggs in southern California, were studied. The duration of the egg, larval and pupal stages at 26.7°C were 0–1, 7 and 9 days, respectively. Sacciform larvae, which developed gregariously within host eggs, were motile until about five days of age, and then became sessile. Parasitized host eggs changed from whitish and soft when freshly-laid to yellow-orange and hard at five days and older. This change was accompanied by formation of septal walls separating the mature larvae and pupae. The rate of immature development had a strong positive linear relationship (R2=0.853, n=98) with temperatures in the range of 20.0–30.3°C. The theoretical minimum threshold for immature development was 13.5°C, and the required heat units were 241.0 degree-days. Adult eclosion from host eggs occurred mostly (85%) on the first two days of emergence. Although most females emerged during the morning hours (0600–1200 h), males tended to emerge earlier than females with equal emergence during the morning and late night hours (2400–0600 h). The rate of successful adult emergence was high (88%). The ratio of eclosed adults to the number of exit holes was 1.18, indicating that most adults tended to independently cut their exit holes. The number of exit holes had a strong negative relationship (R2=0.711, n=125) with exit hole size, suggesting that larger numbers of developing immatures per host egg result in an overall decrease in adult size.

[In 1919 work on the genus Oneilella was begun by the author and Mr. R. E. Turner. General agreement was reached as to the species represented in the material studied, and a table constructed before Mr. Turner's return to S. Africa. Subsequently all the additional material now dealt with was seen by Mr. Turner, and determined in collaboration.]

The genus Oneilella, Cam. 1904, created for the reception of Cryptus formosus, Brullé 1846, has up to the present remained monotypic. That it contained many more species was evident after an examination of the examples of this genus available in the British Museum collection and in various collections forwarded for identification to the Museum or received through the Imperial Bureau of Entomology. The material so gathered together (over 450 specimens) is, with one doubtful exception, African in source and dates from 1848 onwards. Its analysis has been a matter of some difficulty and has been undertaken chiefly because of the economic importance of some of the species. In the following pages an attempt has been made to summarise our present knowledge of the genus and its parasitism, and to describe such forms as appeared to be new.

During November 1926, a few days were spent in making a rapid investigation of the insect pests of cotton occurring on the coast of Kenya Colony, between Mombasa and Mambrui, some eighty miles to the north.

The pink boll-worm, Platyedra gossypiella, Saund., was found to occur in every plot of cotton visited ; it was also noticed that a certain proportion of the worms were parasitised by a species of Braconid, which has been described above by Mr. D. S. Wilkinson under the name of Microbracon kirkpatricki.

A second visit was paid to the coast during the beginning of February 1927, to ascertain to what extent, if any, the pink boll-worm was controlled by this parasite, and to report on the possibilities of its introduction to other countries.

Owing to the short time available for this work, these notes are naturally very incomplete ; it is hoped however that they will be of some value should anyone be of the writer's opinion that it is well worth while attempting to introduce this parasite into other countries.

Embryo development in eggs of the spittlebug Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) passes through four phases (known as S1 to S4) being stopped at S2 during diapause. Studies about the molecular basis of diapause in spittlebugs are nonexistent. Here, we analyzed proteins from non-diapausing (ND), diapausing (D) and post-diapausing (PD) eggs of the spittlebug M. spectabilis. In total, we identified 87 proteins where 12 were in common among the developmental and diapause phases and 19 remained as uncharacterized. Non-diapausing eggs (S2ND and S4ND) showed more proteins involved in information storage and processing than the diapausing ones (S2D). Eggs in post-diapausing (S4PD) had a higher number of proteins associated with metabolism than S2D. The network of protein interactions and metabolic processes allowed the identification of different sets of molecular interactions for each developmental and diapause phases. Two heat shock proteins (Hsp65 and Hsp70) along with two proteins associated with intracellular signaling (MAP4K and a serine/threonine-protein phosphatase) were found only in diapausing and/or post-diapausing eggs and are interesting targets to be explored in future experiments. These results shine a light on one key biological process for spittlebug survival and represent the first search for proteins linked to diapause in this important group of insects.

Multiple mark-release-recapture experiments were carried out on females of three anthropophilic populations of Aedes simpsoni (Theobald) complex at Nkokonjeru and Bwamba in Uganda to determine and compare the population size, survival rates and longevity of the adult stages. There were high recapture rates (26.23%, 2 7.42% and 28.28%) at the different sites. The population sizes, estimated by Jolly's stochastic method for the three sites (465, 561 and 675 female mosquitoes) were not significantly different, neither were the survival rates of the females (0.6026, 0.7145 and 0.8152). Other parameters estimated for the three populations were also similar. Population size estimates by Jolly's stochastic model and the simple Lincoln Index methods were not in agreement. The other method over-estimated population size. Since the estimated parameters for the Nkokonjeru population are similar to those of the Bwamba populations, there is a potential for the transmission of yellow fever virus to the human population at Nkokonjeru, as at Bwamba.

Experiments were conducted in Bangladesh in April–July and July–December to study the effectiveness of three methods of insecticide application to three varieties of rice against the stem-borers Scirpophaga incertulas (Wlk.) and Chilo polychrysus (Meyr.). In April–July, seedlings of the varieties IR8 and Dacca-14 were uprooted when 22 days old and treated individually with 0·0375%, 0·075%, 0·15% or 0·3% diazinon (as Diazinon 60 EC), dicrotophos (as Bidrin 85 EC) or carbaryl (as Sevin 85 SP) or 0·3% γ-BHC dust for 12, followed by dipping for 12 h in fresh water and then transplantation. In July–December, the same treatments were applied by controlled irrigation to the seedbeds of the varieties IR8 and Dacca-25 and for 40 h when the seedlings were 24 days old. In another experiment in July–December, granular formulations of diazinon (as Diazinon 5G), dicrotophos (as Bidrin 5G) and Sevidol (a mixed formulation of carbaryl 8G plus γ-BHC 8G) were also applied to the transplanted field at an interval of 20 days. Insecticides applied to uprooted seedlings reduced borer populations more in the case of variety IR8 than in Dacca–14. Diazinon applied at 0·3% to the variety IR8 and Dacca–25 effectively reduced the borer population to 4–8 and 10·5%, respectively, for up to 41 days; γ-BHC applied to the seedbed did not show much response. Dicrotophos was not highly effective in controlling the borers. Granular formulations of Sevidol at 1–5, 2 and 2–5 kg a.i./ ha and diazinon at 2–5 kg a.i./ha controlled stem-borers more effectively in variety IR8 than in Dacca-25. Variety IR8 was found more susceptible to the stem-borers than Dacca-25 and Dacca-14.

A DDT sol, prepared in glass dishes in the manner described, has a reproducible zeta potential of −25 mv. Electrophoretic measurements showed that DDT conditioned in cardboard cartons has a zeta potential of zero.

The zeta potential of the suspension behaves in a predictable and measurable manner in the presence of mono-, di-, tri-, and tetravalent ions.

Spectrographic analyses showed that there are two identifiable sources of ions: (1) the DDT, and (2) the cardboard container. A third source of ions was indicated as being, singly or together, the distilled water and/or the DDT solvent.

Spectrographic data showed that ions were associated with the conditioned DDT.

In glass containers, a poor source of ions, kill of larvae of Anopheles quadrimaculatus Say was higher than in paper containers, a good source of ions. These data are correlated with the zeta potential and flocculation behaviour of DDT suspensions.

Experiments were carried out in Kenya to find whether insecticidal smokes from “Swingfog” machines would remove tsetse flies, in this instance almost all Glossina longipennis Corti, carried by trains. Fogging was done by two operators, each with a machine, starting from opposite ends of trains halted at a station twenty miles inside a fly-infested area and assessment was by routine catches at a station twenty miles outside it. It was found that fogging reduced the number of flies found on trains by 60 to 70 per cent. As the trains had to pass through a light fly infestation after fogging, the real kill is likely to have been higher. The cost of such partial reduction is believed to be considerably higher than would be that of therapeutic control of trypanosomiasis in the affected region.

A technique is described for exposing insects to insecticidal deposits on detached foliage. Treated leaves are laid horizontally on boards with their petioles projecting through holes into water. Each insect is confined to the leaf surface by a small glass ring coated on its inner side with polytetrafluoroethylene and surrounded by a heavy metal ring to hold the leaf flat. This method is satisfactory for insects that do not spin webs and are unable to take off at a steep angle.

The pseudopupa and last larval instar of Epicauta erythrocephala, Pall., have remained undescribed up to the present, although the economic importance of the insect is very great, the beetle being an important pest of many cultivated plants and its larva a parasite of locust egg-pods. These stages are, however, figured in the work of I. Portchinsky, published in 1914, but in the figure of the pseudopupa the stigmata on the three thoracic segments are omitted.

During investigations made in early spring (1926–1927) in the environment of Old Bukhara, I found a great quantity of the pseudopupae and larvae of the last instar of E. erythrocephala in the soil. In the early spring of 1929 the same instars were reared in the insectary of the Agricultural Experimental Station at Shirabudin (Old Bukhara).

Tambunan is an elevated and isolated plain in the interior of North Borneo, occupied by irrigated paddy cultivation, surrounded by jungle-covered hills, and inhabited by a primitive native population subject to severe malaria.

The Malaria Research Department of North Borneo carried out surveys in this locality during 1939–42 for larval and adult Anopheles as part of an investigation into the causes and control of malaria in Borneo. The main findings of this work, and the incrimination of A. leucosphyrus, Dön., as a vector of malaria, have been described elsewhere (McArthur 1947), but brief accounts are given below of the habits and characteristics of the Anopheles in the locality.

Since a fairly extensive collection of the Braconid genus Spathius, largely comprised of bred series of new species, had lately been received for identification by the Imperial Institute of Entomology, and since there were various species in the British Museum awaiting description, it was considered opportune that I should attempt some sort of revision of this comparatively little worked but nevertheless quite interesting group : it is hoped to publish my results shortly. In the meanwhile, however, the following descriptions are presented since most of these names are required at an early date for inclusion in a paper on the biology of these parasites.

The following new species was reared from the eggs of a Pentatomid bug, Tectocoris lineola, F. (banksi, Don.), which attacks cotton. It occurred in company with Hadronotus nigricornis, Dodd, and was more abundant than that species.