This is an account of work carried out in Kordofan on behalf of the Imperial Institute of Entomology. The period August-September 1931 was occupied with preliminary surveys and observations on hopper bands. From July to September 1932 and from March to July 1933 the ecology of the solitary phase of Schistocerca gregaria was studied at Um Darag ; and in January 1933 a locust survey of the more northern parts was carried out.

1. A general account is given of the habits and distribution of Tectacoris lineola, together with a description of the adult, and some remarks on the influence of weather conditions on mating.

2. The eggs and the different instars are described, and the period of time occupied by each is given.

3. The connection between Tectacoris lineola and boll rot incidence is established.

4. A table is given illustrating the comparative effect of boll rots and bollworm damage in the past season (1924–1925) on the Cotton Research Farm.

5. The effect of bug punctures on cotton seed and its infection with Fusarium moniliforme are briefly discussed.

Environmental risks associated with the use of non-indigenous organisms for augmentative biological control have received growing attention. In Europe, the native pentatomid predator Picromerus bidens (Linnaeus) has been considered a potential alternative to the North American pentatomid Podisus maculiventris (Say) for the control of lepidopteran, coleopteran and hymenopteran defoliator pests. In the current study, prey consumption and developmental duration of the predatory stages of P. bidens and P. maculiventris were investigated at three temperatures (18, 23 and 27°C) in the laboratory using caterpillars of Spodoptera littoralis as prey. Development time from second to fifth instar was longer for P. bidens than for P. maculiventris, taking on average 17–44 and 14–32 days, respectively, at the different temperatures. Total nymphal consumption of fourth instar S. littoralis caterpillars indicated a greater voracity of P. bidens as compared with P. maculiventris at both the low and high temperatures tested (18 and 27°C). At 23°C, however, the predation rate of P. maculiventris nymphs exceeded that of P. bidens nymphs. Effect of temperature on the functional response of P. bidens to densities of fourth instar Spodoptera exigua was assessed on potted green bean plants. Female adults of P. bidens exhibited a type II functional response at 18 and 23°C but a type III response at 27°C. Searching efficiency was not affected by temperature but handling time decreased from 4.2 to 1.4 h as temperature increased from 18 to 23°C. However, the predator spent twice as much time handling prey at 27°C (2.9 h) than at 23°C. This study indicates high predation rates of P. bidens at a wide range of temperatures and suggests that the species may be a valuable asset for the biological control of defoliating caterpillars, provided that obstacles to its mass production can be overcome.

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.

Continuous ingestion of the phloem sap of plants by aphids can remove a significant amount of photoassimilates. Based on our earlier works, we hypothesized that due to the reduced aphid feeding time caused by antibiosis, wheat plants may achieve growth tolerance to aphids. We tested this hypothesis using three wheat cultivars, XY22 (Xiaoyan22), AK58 (Bainongaikang58) and XN979 (Xinong979) and the grain aphid, Sitobion avenae. In the choice test, S. avenae did not show any preference among the three wheat cultivars. However, S. avenae had a lower body weight and a lower intrinsic rate of increase when feeding on XY22 than on AK58 and XN979. The electrical penetration graph results indicated that S. avenae had significantly shorter mean and total phloem ingestion periods on XY22 than on AK58 or XN979. The aphids required a similar time to reach the phloem sap on the three wheat cultivars, but required more time to establish sustained phloem ingestion on XY22. These results suggest that the resistance factors of XY22 may be phloem based. Moreover, XY22 suffered less biomass loss in response to aphid infestation compared with XN979, suggesting that XY22 also had a better growth tolerance to S. avenae than XN979. Wheat resistance level to S. avenae was partially correlated with plant photosynthetic rates, and peroxidase activities. These results confirmed that the limitation in aphid feeding from plant phloem in wheat cultivar XY22 was related to antibiosis but not antixenosis, which caused XY22 tolerance to S. avenae.

During the winter months, when larval populations of shoot flies (Diptera, Acalypterae) are relatively static, pure clumps of grasses in southern England were sampled. The tillers were dissected and the shoot-fly larvae removed and identified to determine what species were present and how and in what numbers they were distributed within the species of grasses. Concurrently, a permanent pasture was sampled in which the grasses were closely intermixed, and it was found in the two cases that the same host preferences of the insects were broadly maintained. Those preferences are due to the selectivity of the ovipositing female rather than the dietary requirements of the larvae, which are facultative parasites of most grasses and cereals.

A Table is given of the relative abundance of the larvae of 17 species in 16 different grasses and indicates the degree of host specificity of each insect. For example, Oscinella frit (L.), the frit fly of oats, is found in 11 of the common grasses but not in Dactylis glomerata whereas O. albiseta, (Mg.) is found only in this grass.

Horizontal migration of larvae from tiller to tiller can take place; vertical migration may also take place from ploughed-in grasses to cereals sown above. It is shown that migration is mainly limited to autumn and spring when soil temperatures are above the thermal threshold of activity of the larvae.

Calyptrate fly populations were monitored with sticky traps at the following sites in Hampshire, UK during August to November 1998: a landfill and composting site (Paulsgrove), a site adjacent to this landfill (Port Solent), a site with no landfill nearby (Gosport), and a composting site with no landfill nearby. Overall, house flies Musca domestica(Linnaeus) and lesser house flies Fannia spp. were not important constituents of the dipteran catch, while bluebottles (Calliphora spp.) and greenbottles (Lucilia spp.) comprised approximately 12% of the total. Very large fly populations were found at the two composting sites, and it seems likely that these provide ideal breeding grounds for a range of fly species since they offer an abundance of warm decaying organic matter. Large fly populations were also evident at the landfill site. The suitability of household waste for the development of calyptrate Diptera was confirmed in a controlled trial: a mean of 0.43 adults emerged per kilo of one-week-old waste. Since many hundreds of tonnes of waste are delivered to the landfill daily, it is clear that the landfill is likely to substantially increase the local population of calyptrate flies. However, the data suggest that there was little movement of Diptera from the landfill to Port Solent situated approximately 500 m away. The most important calyptrate flies at this site were the cluster flies Pollenia rudis (Fabricius) and P. amentaria (Scopoli); the landfill site is unlikely to provide a suitable breeding site for these flies, as the larvae develop as parasites of earthworms. Significantly more flies emerged from one-week-old than from two-week-old household waste. A comparison of different barriers to the emergence of adult house flies from waste demonstrated that sacking provided an effective barrier to fly emergence, but that soil did not differ significantly from control treatments. If managed appropriately, it seems that the use of sacking over landfill waste could substantially reduce associated fly populations.

Evidence is given, based on, field observations and experiments, of damage to fruits of cacao by two species of Amblypelta (A. theobromae Brown in New Guinea and A. cocophaga China in the British Solomon Islands); the nature of the damage is described.

A summary is given of the feeding habits generally, and the effects on the plants attacked, of members of the genus Amblypelta.

Comprehensive lists of the known food-plants of each species of Amblypelta are given.

Further studies were made of G. medicorum and G. fusca using the resting-haunt technique.

During 5½ collecting days, 200 G. medicorum and G. fusca were taken by the resting-haunt technique ; over this period, only one fly was taken by the normal, human bait technique.

Out of 119 G. medicorum 45 per cent, were females, and out of 73 G. fusca, 44 per cent, were females ; the resting-haunt technique yields a good cross-section of the tsetse population.

Out of 15 recently gorged G. medicorum and eight G. fusca examined, all contained mammalian blood. Gorged flies were very numerous, so that it should be possible to ascertain the wild hosts by the precipitin test.

From the evidence available, it is believed that at the end of the rains both G. medicorum and G. fusca feed only during the twilight hours, or when the forest is fully illuminated by the moon.

The false codling moth (FCM), Thaumatotibia leucotreta (Lepidoptera: Tortricidae) is an insect pest which represents an important threat to the production and marketing of a wide range of agricultural crops in the African-Caribbean-Pacific (ACP) countries. The FCM reduces not only the yield and quality of the crop but also as a quarantine insect pest, restricts the trade of susceptible agricultural produce on the international market. In addition, little research has been conducted in the ACP countries on the bio-ecology and sustainable management of this pest, especially on vegetables for export. Thus, action-oriented research aimed at understanding the bio-ecology of this important pest is essential to achieve effective management. Various management interventions against this pest have been used in some parts of the world, especially in South Africa on citrus. Currently, farm sanitation is regarded as the key management strategy. Exploring and improving on other interventions such as Sterile Insect Technique, monitoring and mass trapping of male moths, augmentative biological control, use of bio-pesticides, protected cultivation and cold treatment may help to mitigate the expansion of FCM into other countries, especially in the European and Mediterranean Plant Protection Organization region where it has become a regulated insect pest since 2014. This review discussed the bio-ecology of FCM and highlighted some of the challenges and opportunities for its effective management and its implication for international trade, especially the export of chillies from the ACP countries into the European Union market which requires strict phytosanitary regulations.

A key to the fully grown larvae of 11 species of Phycitinae is given. Of these, the following eight are known in Britain either as stored-products pests or associated with imported food:— Ephestia elutella (Hb.), Anagasta kuehniella (Zell.), Cadra cautella (Wlk.), C. calidella (Gn.), C. figulilella (Gregson), Plodia interpunctella (Hb.), Mussidia nigrivenella Rag. and Ectomyelois ceratoniae (Zell.). The key is preceded by a brief account of the economic importance of these species in Britain.

The other three species are Ectomyelois decolor (Zell.), E. muriscis (Dyar) and Paramyelois transitella (Wlk.). Although these are native to the Americas and are unknown in Britain, they comprise, together with E. ceratoniae, the economically important species formerly of the genus Myelois Huebner.

The larvae of Mussidia nigrivenella, P. transitella and of the three species of Ectomyelois are described.

Field studies suggest that the generalist carabid predator and scavenger Pterostichus melanarius Illiger aggregates to patches with a higher density of slug prey. The mechanisms behind such aggregation are unknown. Experiments were conducted to test the hypothesis that they are responding to chemical cues. Electroantennograms (EAGs) showed no response by P. melanarius antennae to live, nematode-infected, injured or freshly killed slugs, but a strong response to dead slugs that had been allowed to decay for up to 48 h. Such a response would enable the beetles to find carrion in the field and may also, as dead prey are likely to be spatially correlated with live ones, provide a mechanism by which P. melanarius finds patches with a higher density of live slugs. Subsequent video analyses of P. melanarius responses to patches of slug mucus within arenas showed that beetles with intact antennae could detect these patches because they spent more time, and moved greater distances, within them and increased their rate of turning. Thus, at close range, P. melanarius used their antennae to detect slug mucus and hence, by implication, live slugs. The apparent contradiction between EAG data and behavioural experiments is discussed. Together these result confirm that P. melanariusdoes respond to chemical cues from its slug prey in ways that could lead to aggregation in areas of higher slug density in the field.

The biology and economic status of aphids attacking rice throughout the world is reviewed, as is the literature concerning other aphids found in or near irrigated rice fields but not usually infesting rice. Altogether, 37 species of aphids belonging to seventeen genera are considered. The aphids are dealt with in two similar–sized groups according to their feeding sites, namely root–feeding and leaf–, stem– and ear–feeding species. Aphis craccivora Koch and Myzus persicae (Sulz.) are regarded as ‘occasional rice aphids’ as they are found on rice occasionally but do not regularly infest rice plants. A. gossypü Glov. is treated as a ‘rice aphid’ although its occurrence on rice plants is also sporadic. In addition to the literature survey, additional information is given based on field collections and observations, on the rice aphid component of more than 18 000 aphids trapped in yellow pan traps, on the natural enemies reared and collected and from laboratory experiments in Japan. Unpubished information was also extracted from the data labels of the British Museum (Natural History) aphid collection. The ecological relationships between rice aphids and aphids associated with weeds near irrigated rice fields in the Yamaguchi area of Japan is discussed. Three of the rice aphids were found on 22 species of weeds and the three ‘occasional rice aphids’ also occured on 22 species of weeds. A total of 43 species of weeds harboured aphids.

Cotesia urabae is a solitary larval endoparasitoid that was introduced into New Zealand in 2011 as a classical biological control agent against Uraba lugens. A detailed knowledge of its reproductive biology is required to optimize mass rearing efficiency. In this study, the courtship and mating behaviour of C. urabae is described and investigated from a series of experiments, conducted to understand the factors that influence male mating success. Cotesia urabae males exhibited a high attraction to virgin females but not mated females, whereas females showed no attraction to either virgin or mated males. Male mating success was highest in the presence of a male competitor. Also, the time to mate was shorter and copulation duration was longer when a male competitor was present. Larger male C. urabae had greater mating success than smaller males when paired together with a single female. This knowledge can now be utilized to improve mass rearing methods of C. urabae for the future.

Changes in the genetic structure and genotypic variation of the aphid Sitobion avenae collected from cereal crops in northern France were examined by analysing variation at five microsatellite loci across several years and seasons. Little regional and temporal differentiation was detected, as shown by very low FST among populations. Repeated genotypes, significant heterozygote deficits, positive FIS values and frequent linkage disequilibria were found in nearly all samples, suggesting an overall pattern of reproductive mode variation in S. avenae populations. In addition, samples from Brittany (Bretagne) showed greater signs of asexual reproduction than those from the north of France, indicating a trend toward increasing sexuality northward. These patterns of reproductive variation in S. avenae are consistent with theoretical models of selection of aphid reproductive modes by climate. Contrasting with little changes in allelic frequencies, genotypic composition varied substantially in time and, to a lesser extent, in space. An important part of changes in genotypic arrays was due to the variation in frequency distribution of common genotypes, i.e. those that were found at several instances in the samples. Genotypic composition was also shown to vary according to climate, as genotypic diversity in spring was significantly correlated with the severity of the previous winter and autumn. We propose that the genetic homogeneity among S. avenae populations shown here across large temporal and spatial scales is the result of two forces: (i) migration conferred by high dispersal capabilities, and (ii) selection over millions of hectares of cereals (mostly wheat) bred from a narrow genetic base.

Variations in density of adults of Anopheles merus Dön. in Jimbo Village on the Kenya Coast were found to be correlated both with rainfall and with salinity at their breeding sites. Densities started to increase at the beginning of the rains when several breeding sites were formed. This was followed by a decline in numbers resulting mainly from the decrease in salinity in the semi-permanent breeding sites. A second rise occurred after the end of the rains, corresponding with an increase in salinity in the semi-permanent breeding sites due to evaporation. Peak density coincided with salinities of 30–50% sea water in the breeding sites. Laboratory breeding experiments showed that the larvae were usually capable of completing development in 0–100% sea water, with optimum development at 0, 40 and 60% sea water. Failure to complete development in 100% sea water at certain periods of the year indicated that there could be some seasonal variation in salt tolerance. The larvae were also found to complete development in alkaline saline water collected from an inland location around Lake Jipe in Kenya. The LC50s of sea water for first and fourth-instar larvae after exposure for 2 h were 135·0 and 930·0%, respectively. First-instar larvae were less to lerant of sodium chloride than of sea water of equivalent strength. The LC50 of sodium chloride for first-instar larvae was only 102·5%, sea water equivalent. In tests against first-instar larvae of other soluble chemical salts normally present in sea water, the highest LC50 (122·0g/litre) was of sodium sulphate and the lowest (10·5g/litre) of potassium carbonate.

Hibernation of P. papatasii in Palestine is primarily caused by low temperature, but cyclical (? hereditary) factors exist which modify the phenomena of hibernation to a certain extent, as indicated by the following facts.

1. Occurrence of a gradually increasing number of resting larvae during autumn, with a maximum of hibernating larvae in the first winter generations.

2. A gradually increasing prolongation of development during the late summer generation, with a maximum duration of development in the first winter generations in larvae kept at 30°C.

3. The pupation of hibernating larvae kept at 30°C. in spring at the same time as of larvae kept in out-of-door conditions during the winter.

There is always a certain number of resting larvae (2 to 12 per cent.) throughout the summer in otherwise active broods. This inhibition of development shows that a latent inclination to diapause exists in all generations, and that diapause may also be brought about by unfavourable conditions.

No relation could be found between the interval between hatching and oviposition and asthenobiosis.

Cryptolestes pusilloides (Steel & Howe) has, since 1944, become a regularly occurring pest of stored cereals in South America, Australia, South Africa, and to a lesser extent, East Africa, and apparently occurs also in North America as well as in Portugal (where it has recently been found on stored almonds), but has not established itself in flour mills in the U.K., notwithstanding its frequent introduction. Prior to that time it appears to have been very rare. Its life-cycle resembles that of C. ugandae Steel & Howe, and in common with that species and with C. turcicus (Grouv.), it is unable to breed successfully at relative humidities below 50 per cent. Its temperature range is 15–35°C., the optimum for development and fecundity being at about 30°C. at 90 per cent. R.H. Survival was greatest at 27·5°C. and newly formed adults weighed most at 22·5°C. In general, males weighed more than females and their developmental period under any one set of conditions was slightly longer than that of females. The biological information now available shows that C. ferrugineus (Steph.) and C. capensis (Waltl), which are taxonomieally associated by exhibiting sexual dimorphism in the structure of the mandibles, are species that can withstand dry conditions, whereas C. ugandae, C. turcicus, C. pusillus (Schönh.) and C. pusilloides, all of which show sexual dimorphism in the antennae, are unable to breed at relative humidities much below 50 per cent.

The flight performance of a laboratory population of Triatoma infestans (Klug) was tested on a flight balance. Bugs adopted a typical flight posture which is described. They were capable of steady flight and produced reasonable amounts of lift. Flight durations were generally short, but capacity for flight rose to a peak in the third week after adult eclosion with the longest recorded flight being one of 2 h 40 min by a male. Sexual differences were slight; males had a slightly higher mean wing-beat frequency (57·8 Hz against 55·6 Hz), and a few more females than males made longer flights. Differences were noted between short and long fliers; the latter producing significantly more lift and showing signs of a flight pattern divisible into rising, steady and falling phases. The short fliers showed only rising and falling phases. Lift and wing-beat frequency were correlated, but it is evident that lift also depends on other variables such as stroke-plane angle, body angle and wing-beat amplitude, which are discussed.

Cassava intercropped with cowpea in Colombia had lower numbers of Aleurotrachelus socialis Bondar and Trialeurodes variabilis (Quaintance) per leaf and per plant than did monoculture cassava. These differences persisted for up to six months after harvest of the cowpea. These results are examined in light of the natural enemies hypothesis, which suggests that natural enemies may be favoured in diversified systems, thereby reducting herbivore load. In this regard, the effects of different cropping systems on the whitefly predator Delphastus pusillus (Le Conte) and on the combined action of the parasitoids Amitus aleurodinus Haldeman and Eretmocerus aleyrodiphaga (Risbec) are discussed. D. pusillus displayed a functional responce and was more abundant in monocultures than in intercrops. Predator:prey ratios were similar between treatments and so low that predation appeared to have little impact on whitefly numbers. Parasitism levels of Aleurotrachelus socialis were not affected by crop combinations. The data suggest that the activity of the natural enemies does not explain cropping system effects on cassava whitefly populations.