The biology of Eulophonotus myrmeleon Fldr., the larva of which bores in the woody stems and branches of cocoa throughout West Africa, was studied in Ghana and Nigeria. In the laboratory the adult lives for a maximum of four days during which about 500 eggs are laid. The larval period is not less than three months and the pupal stage lasts three weeks. Larvae desert galleries in drying wood, and the excavation of new galleries in fresh wood is begun beneath the protection of a tent of wood particles bound together with silk. Populations are seldom large enough for their activities to be serious in Ghana, but the severe dry season in Western Nigeria causes considerable die-back in cocoa, creating conditions favouring larval migration and thus increasing the injurious effects of E. myrmeleon.

Stathmopoda auriferella (Wlk.) (Lepidoptera, HELIODINIDAE) is recorded as a pest in Northern Nigeria of sorghum in the field and on the head in store. Notes are given on the nature of the infestation. The mature larva is described, and characters are listed for separating it from the larvae of four common species of Lepidoptera which infest stored produce; and for separating the adult from that of Sitotroga cerealella (Ol.).

Observations made in Uganda on eight individuals of the mosquito Toxorhynchites brevipalpis conradti Grünb. reared in captivity from egg to adult are recorded. Larvae of this species are predatory and coexist in tree holes with those of mosquitos of medical importance.

The identification of larvae and pupae is discussed, and information provided on the following subjects: the amount of food (living larvae of Aedcs acgypti (L.)) needed for larvae to complete development; the feeding and killing behaviour of fourth-instar larvae; duration of the pupal stage; and the rate of autogenous ovarian development in the unfed female adult.

The compulsive killing behaviour shown by a fourth-instar larva about two days before it pupates could be expected to cause the death of all the other mosquito larvae in a tree hole of average size. This species is unusual among mosquitos in that pupae of females developed more rapidly than those of males.

Details are given of the design, construction and use of a new apparatus for use in the operation for removal of the corpora allata of locusts and in certain operations within the head capsule.

A method of assessing the physical condition of grain residues is described. It consists of utilising data obtained by taking the weight and volume of samples before and after sieving over a 1/10-inch mesh.

The application of this method to a survey of the insect population of wheat residues beneath the floor of a small granary in southern England is described. Information from the weight and volume data obtained enabled the samples to be classified in a manner agreeing with visual estimates. It had the advantage of objectivity.

Three vertical series of samples were taken and analysed, and the insects present counted and identified. The size, composition and distribution of the insect population is briefly discussed in relation to the condition of the residues and their depth below the surface. The fauna consisted of grain pests (Sitophilus granarius (L.), Oryzaephilus surinamensis (L.), Ptinus tectus Boield., P. fur (L.) and Hofmannophila pseudospretella (Stnt.)) and incidental species (fungus feeders and ground-dwellers) and the two groups differed in their distribution and in their apparent response to the physical conditions.

In view of the sporadic nature of outbreaks of Gryllus bimaculatus Deg., all stages of this cricket were reared in Israel at various temperatures in order to find the effect on its development and fecundity. Eggs were incubated at constant temperatures and also at fluctuating room temperatures. The mean incubation period varied from 7·5 days at 34°C. to 75 days at a mean of 16·4°C.; at 26°C., at which the percentage hatching was greatest, it was 14 days; and the threshold of development was calculated to be about 15°C. For larvae reared at constant temperatures on a diet of bread and fishmeal, the development period varied from about 32 days at 34°C. to 130 days at 22°C.; the threshold was calculated to be 19°C. For adults maintained at constant temperatures, the mean life at temperatures of 26 to 34°C. usually exceeded one month, the preoviposition period varied from 4 days at 34°C. to about 15 at 22°C., and the threshold of reproduction was calculated as 19°C. Of 16 females tested that had been reared and maintained at near optimal temperatures (30–34°C.), more than half gave rise to upwards of 500 larvae each, and two to over 3,000 each. The reproductive capacity was affected by the temperature at which the larva was reared, the number of offspring produced being greatest from pairs of adults reared at 26°, and nil from females reared at 37°C. Light-trap catches during three years showed a peak in midsummer or autumn.

Ten nominal species of DELPHACIDAE have hitherto been regarded as synonymous with Sogata, furcifera (Horv.), which is notorious as a pest of Graminaceous crops in eastern Asia. In a recent study it was established that two members of this complex represented distinct species, and it was accordingly considered necessary to re-examine the status of the remainder: the results of such a study are reported in this paper. The members of this complex now recognised as distinct species number more than twenty: some are restored from synonymy and others are described as new, and all, as appropriate, are referred to one of three genera, Matutinus Distant, Sogatella Fennah (here accorded generic status) and a new genus, Sogatodes. Most of the species in the complex are redescribed and a key is given for the separation of all.

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.

Experiments in south-east England are described in which insecticides were tested against the Carabid beetles Harpahis rufipcs (Deg.) and Feronia melanaria(111.), which cause damage to strawberry fruits.

In preliminary screening tests, the mortality of H. rufipex was low when adults were caged with fruits or straw treated with rotenone at 0·004 per cent, or with carbaryl, DDT, dimethoate, malathion, mevinphos, nicotine, TEPP, toxaphene and trichlorphon at one or more concentrations in the range 0–06–0–2 per cent. In small-scale field trials, γ BHC at 0·026 per cent, gave poor results but chlordane and dieldrin exhibited persistent toxicity.

In further tests with fruits, field-weathered deposits from sprays containing 0·1 or 0·2 per cent, dieldrin caused over 90 per cent, mortality for 7 and 21 days, respectively, but left residues at harvest of 0·5 p.p.m., which were considered too high for consumer safety.

Dieldrin applied to soil at 5 lb. per acre resulted in 100 per cent, mortality for 28 days in 1957, but gave very variable results in 1958. Conversely, aldrin at 5 lb. gave effective mortality for only 14 days in 1957 but for the maximum test period of 89 days in 1958; no satisfactory explanation was found for the seasonal differences. Aldrin at 10 lb. per acre gave 100 per cent, mortality for 77 and 89 days, respectively, in the two years. Tests of soils into which measured quantities of insecticide had been incorporated, resulted in 100 per cent, mortality, after 4 days' exposure, with aldrin and dieldrin at levels of 2–4 and 16–32 p.p.m., respectively; endrin at 64 p.p.m. was only slightly toxic.

In field trials in 1959–60, application of aldrin at 10 lb. per acre to the surface of the soil around the plants in sprays in late April immediately before flowering, or at 5 lb. per acre in late May before laying straw below the fruit, reduced fruit damage due to H. rufipes or F. melanaria by 66–94 per cent. Residues at harvest were of the order of 0·03 p.p.m., and no effect on flavour was detected in processed fruit from plots treated at either time of application.

An operation is described in which approximately 100 sq. miles of heavily infested tsetse country in Southern Rhodesia, supporting both Glossina morsitans Westw. and G. pallidipes Aust. and an abundant and varied game population and formerly an area of endemic sleeping sickness attributable to Trypanosoma rhodesicnse, received six applications of 4 per cent, γ BHC in diesolene, discharged from aircraft in the form of a coarse aerosol, between May and September 1957. The area was a valley bounded by an escarpment, which provided conditions of relative isolation.

Fly-round catches of G. morsitans taken before, during and after the operation indicated that in those parts of the area that had received uniform treatment an estimated reduction in population, after the final application, of between 96·6 and 100 per cent, had been achieved, but where only the vegetation forming the riverine fringes had been treated the reduction was less. Quantitative data on the effect of the treatment on G. pallidipes were not collected, but the species ceased to be found in an investigation on sampling techniques that had been in progress in the area.

The area had been chosen for a resettlement scheme of indigenous people that was due to begin before October 1957, and the purpose of the spraying operation was to reduce the population of tsetses to a level that would permit the introduction of the people and their stock with comparative safety from trypanosomiasis. It was hoped that the number of people to be resettled would be sufficient to clear most of the tsetse habitat in their text-abstract agricultural activities and that the tsetses would be permanently excluded from the valley. Four to five years after the start of resettlement there were still several uncleared areas remaining, but the situation was continually improving, and estimates in 1962 indicated that the population of G. morsitans had remained at a low level, showing a reduction of between 81 and 100 per cent, as compared with that prevailing before the spraying operation. The stock introduced in 1957 were maintained under drug treatment, and the rate of infection with T. congolense was kept below a 3 per cent, level; no cattle died from trypanosomiasis, and their numbers had more than doubled by 1962. No case of sleeping sickness occurred.

The work described here showed that, under conditions of relative isolation, G. morsitans can be sufficiently reduced in numbers by means of an insecticidal aerosol discharged from aircraft to permit the successful introduction of people and stock, provided that adequate veterinary supervision is given, and that under these conditions settlement can prevent the recovery of a population of this species.

In order to seek at least a partial explanation of the differential occurrence of Cryptolestes turcicus (Grouv.) and C. ferruginous (Steph.), the interaction between different combinations of the larvae of the two species was studied when each newly hatched larva was provided with 12·5 mg. wheatfeed. It was found that the numbers of C. turcicus surviving to the adult stage in the presence of C. ferrugineus was a linear function of its own initial numbers, whereas the survival of C. ferrugineus seemed to be some function of the size of the environment. This conclusion, taken together with other data, suggests that if the two species were to gain access to cereals together, dry conditions, coarse food, low larval density and the availability of refuges for pupation would favour high populations of C. ferrugineus, whereas moist conditions, fine food, moderate to high larval density and the absence of refuges for pupation would favour high populations of C. turcicus.

The local blowflies were sampled by bait-trapping at a number of stations in the Northwest Highlands of Scotland and their western seaboard, the Western Isles and eastern and southern England, to supplement the results of an earlier survey of the distribution of Calliphorine blowflies in Great Britain.

Of the species of Lucilia, L. richardsi Collin was as numerous as L. scricata (Mg.) in the south-east, but relatively infrequent further north, and was not found in the Northwest Highlands or Islands. L. ampullacea Villen. and L. silvarum (Mg.), though earlier found in the eastern part of the Northwest Highlands, are rare or absent on the western seaboard and in the Western Isles. L. illustris (Mg.) is relatively infrequent in the Northwest Highlands and Islands, but in these regions was found as far north as Lairg, and in the Outer and Inner Hebrides.

Of the species of Calliphora, neither C. loewi End. nor C. uralensis Villen. were found in any of the eight stations in eastern and southern England. C. uralensis was common in the Western Isles and on the northwest seaboard. C. loewi more common in the Central Highlands and apparently absent from the Islands.

Acrophaga subalpina (Ringdahl) was not taken in the stations in the east and south of England, Cynomyia mortuorum (L.) only in the three more northerly of these, north and west of the Wash, and Phormia terraenovae R.-D. at onlv one station further south, Wye.

The known external characters, and some new ones, for separating the sexes of pupae and adults of stored-products Coleoptera are described and in many cases figured.

Four methods have been tested of dividing cultures consisting of wheat grains containing larvae and pupae of Sitophilus granarius (L.) into samples weighing just under 10 g. and suitable for use in fumigation experiments. Two mechanical methods, each dividing a culture into two equal parts, the division being successively repeated to yield 32 samples, were shown to be satisfactory in every trial. One apparatus divided the culture on the chess-board principle, the other by means of radial fins equally spaced round the circumference of a conical divider. The standard method used at the Pest Infestation Laboratory also proved satisfactory; it consists of scooping up samples by hand radially, at random, from a culture dispersed symmetrically by pouring it over the bottom of a spherical flask, but it was evident that personal bias could be introduced by its use. The fourth method, consisting of ‘ random scooping ’, is widely used but yielded samples having considerable heterogeneity from all cultures containing larvae older than the late third instar and having a density exceeding one insect in 30 grains of wheat. This method was the only one that divided standard cultures into samples showing heterogeneity in their age structure. When cultures with an age range of only four days were divided, all four methods yielded samples for which the emergence curves were heterogeneous, apparently as a result of heating induced in samples as small as 9 g. as a result of the metabolism of the larger larvae.

The dispersion of groups of adult grain weevils (Sitophilus granarius (L.)) was investigated under controlled conditions by observing the numbers occurring on the surface, or at various depths below it, in small bulks of grain. The effect of population density, and temperature and moisture content of the grain, on numbers at the surface was studied by using groups of weevils in 500 g. wheat, and on dispersion in the vertical plane by confining weevils, isolated or in groups of twenty, within a thin layer of 200 g. wheat contained between vertical glass plates, through which the positions of individuals could be recorded.

In grain at 25°C. and 14 per cent. moisture content, the proportion of the population at the surface was about 17 per cent. for densities of 2–100 insects in 500 g., and was only temporarily changed by adding or removing weevils at the surface; the proportion was higher at nine per cent. moisture content or at 15 or 35°C.

In grain at 25°C. and 14 per cent. moisture content, the typical behaviour pattern of individuals consisted of random vertical and lateral movements, so that there was a constant turnover within a group, but at nine per cent. moisture content and 25°C. they tended predominantly to move upwards. At 15 and 35°C., isolated individuals were stationary, but upward movement was elicited by increase in density; relatively static behaviour at 35°C. is thought to be associated with the need for water conservation. The possible relevance of these results to the detection and control of pest populations and their spread in storage conditions is discussed.