Phosphoglucose isomerase (PGI) plays an important role in energy metabolism, and it is documented that PGI exhibits an extensive polymorphism which can affect insects' fitness and adaptation. In this paper, we studied the structural characteristics and polymorphism of pgi gene in the fall webworm (Hyphantria cunea), an important invasive pest in some European and Asian countries. A 2110-bp pgi full-length cDNA encoding a polypeptide of 556 amino acids was obtained from H. cunea. The pgi full-length in the H. cunea genomic DNA was 14,332 bp with 12 exons and 11 introns, similar to the structures of pgi in other Lepidoptera species. We compared the structures of pgi in different insect species. Moreover, thirteen pgi genotypes comprised of five alleles were identified in the Chinese population. Genotypes pgi-cd, pgi-cc and pgi-ce were the most prevalent with over 70% of individuals allocated to them. Four out of five alleles were sequenced the cDNA full-length. Thirty stably variable sites were found among them with five non-synonymous mutation sites. The frequencies of alleles and genotypes were variable in different Chinese geographic subpopulations. Moreover, comparison of pgi mRNA expression levels in each stage of the moth's lifecycle showed that a high expression level was in the 6th instar larval stage, followed by that in the egg and adult stages. The results will provide a basis for further study of the role of different alleles and genotypes of PGI on fitness and adaptation of the moth H. cunea.

The biology of Hydrotaea irritans (Fall.) has been studied at Weybridge since 1973. The flies have failed to mate in cages and only those which have been fertilised before capture have laid viable eggs in the laboratory. In experiments in 1975–76 flies in the field emerged from June onwards but development of the ovaries (noted in seven stages) to the point of ovi-position was not completed until September. Some 1400 larvae were established in culture and, although they had reached a maximum size by January, they continued to feed until 14 March. Pupation lasted for 25 to 32 days during 6 May to 12 June and a total of 185 flies emerged from 4 June to 9 July. The results of these experiments confirm that H. irritans does not diapause and that the species is univoltine.

An atomizer, with controlling hygrostat, has proved to be a very satisfactory humidifier for raising the humidity of a large breeding room without lowering its temperature.

The factors which influence the passage of flying and crawling insects through a doorway were investigated. It was considered practicable to exclude flying insects from a building or to prevent their successful escape from cages or rearing rooms by means of a downward air current if the speed of this in ft./min. multiplied by the ratio of the length through the doorway to its height is not less than 550. A combination of reflex and illuminated edges, smooth shiny walls without a pattern visible to insects, and a floor grid and underlying screening treated with a long-lasting residual insecticide, will, at all natural population densities, reduce to an insignificant level the number of insects that crawl through and survive. Artificially higher densities, as in rearing rooms, may require that the doorway be fitted with sliding doors in addition. These may be arranged to switch on the air current and lights as soon as they are opened.

Lablab purpureus subsp. bengalensis (Jacq.) Verdc. is an important legume of India and Africa. Both aphids, Aphis craccivora Koch and A. gossypii Glover (Hemiptera: Aphididae), are important herbivorous pests of this legume crop. These viviparous females lay nymphs on the leaf surface of this legume plant. Therefore, it is of considerable interest to study whether leaf surface wax chemicals (long-chain alkanes and free fatty acids) of this legume plant served as short-range attractants and oviposition stimulants in both females to lay nymphs. Twenty-one n-alkanes from n-C12 to n-C35 and 11 free fatty acids from C12:0 to C22:0 were identified in leaf surface waxes. Nonacosane and nonadecanoic acid were the most abundant among n-alkanes and free fatty acids, respectively. Both females were attracted towards one leaf equivalent surface wax against the control solvent (petroleum ether) in short Y-tube olfactometer bioassays. A synthetic blend of tetradecane, pentadecane, tetracosane, tridecanoic acid, tetradecanoic acid, and heneicosanoic acid comparable to one leaf equivalent surface wax served as short-range attractants and oviposition stimulants in A. craccivora; whereas a synthetic blend of tetradecane, hexadecane, docosane, nonadecanoic acid, and arachidic acid comparable to one leaf equivalent surface wax acted as short-range attractants and oviposition stimulants in A. gossypii. These results can provide the basis for efficient pest management strategies of A. craccivora and A. gossypii against L. purpureus subsp. bengalensis using host plant leaf surface wax compounds. Further, SEM studies of antennae and forelegs of both aphids were conducted to observe sensilla structures, which help in chemoreception.

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

Anopheles (Myzomyia) farauti Lav. is recorded from the upper reaches of the Nevaka river, south-western Espiritu Santo, New Hebrides, to an altitude of 1,100 ft. and a distance of 12 miles from the coast. The presence of Plasmodium vivax and P. malariae in the blood of children from hill villages with no nearby Anopheline larval habitats is noted. These children, most of whom have never visited the coast, become exposed to infection during prawning trips to the valleys below their homes. The transmission of P. vivax and P. malariae is shown to take place in the interior of Guadalcanal, British Solomon Islands Protectorate, where a proven vector, A. (Myzomyia) punctulatus Dön., breeds at altitudes of up to at least 1,900 ft. above sea level. A. (Myzomyia) solomonis Belkin, Knight & Rozeboom, the status of which as a vector of Plasmodium is unknown, was found breeding at an altitude of 3,000 ft. Neither P. falciparum nor Wuchereria bancrofti were recorded from the hill districts visited. During the investigations several species of Culicines were collected. Features of the larval morphology of some of these are illustrated and briefly discussed in a systematic appendix.

Laboratory studies are reported on Syntomosphyrum albiclavus Kerrich, a Eulophid of interest as a pupal parasite of tsetse flies. Material for a laboratory culture was obtained from puparia of Glossina morsitans Westw. collected in Tanganyika and sent to London by air.

‘ Natural’ and ‘unnatural’ hosts of this parasite were investigated. S. albiclavus parasitised all species of Cyclorrhaphous puparia offered in the laboratory, but has only been recorded from puparia of Glossina under natural conditions. The conditions which make a host suitable for S. albiclavus are discussed. The most important of these is the presence of the ‘sub-puparial space’ in which the eggs are laid, without which the host is unacceptable. S. albiclavus will also breed on dead pupae and in puparia containing other parasites.

The number of parasites emerging from the host puparium is shown to be directly proportional to its weight.

The fecundity of S. albiclavus is shown to be very variable and dependent upon the weight of host material consumed during larval life, which, in turn, reflects the density of parasites in the host puparium from which the females emerged.

The duration of the parasitic phase of the life-cycle and the length of life of the adults are shown to be functions of the temperature. Length of life is also affected by the relative humidity, increased mortality occurring in low humidities and in saturated air, with an optimum for survival at about 80 per cent. R.H.

It is shown that a constant temperature of 35°C. is fatal to the eggs of S. albiclavus.

The age at which females of S. albiclavus become mature was investigated at three temperatures and it is shown that the rate of maturation of the ovaries is a function of the temperature.

At 25°C., females of S. albiclavus are unable to lay eggs until the third day after emergence. The number of offspring produced then falls off with increasing age of the female and very old females, although attacking hosts, are unable to oviposit.

While on a recent visit to Victoria and South Australia, I made an attempt to collect long series of Calliphoras belonging to the subgenera Neopollenia and Proekon; a special visit was made for this purpose to Seaford and to Western Port, Victoria, the type localities of C. hilli, Patton, and C. rufipes, Macquart, respectively. The collections made represent at least seven species of Neopollenia and two of Proekon.

The following Aphids were collected by Professor Guido Paoli, of Chiavari in Italian Somaliland and in Eritrea.

Colorado potato beetle (Leptinotarsa decemlineata, Say) is the main pest of Solanaceae and its survival is mainly dependent on the carbohydrate digestion. Characterizing the gut enzymes may help us with finding effective inhibitors for plant protection. Activity measurements revealed that gut extracts contain α- and β-glucosidase in addition to α-amylase. For larvae, amylase activity was detected only in gut saturated with nutrients. Leptinotarsa decemlineata α-amylase (LDAmy) had optimum pH of 6.0 and was active under 30–40°C temperature measured on a selective α-amylase substrate, 2-chloro-4-nitrophenyl-4-O-α-D-galactopyranosyl-maltoside. HPLC analysis demonstrated dimer, trimer, and tetramer reducing end amylolytic products from 2-chloro-4-nitrophenyl-maltoheptaoside substrate in similar ratio than that of during porcine pancreatic α-amylase (PPA) catalyzed hydrolysis. The 4,6-O-benzylidene-modified substrate (BzG7PNP) is very stable toward hydrolysis by exo-glycosidases, therefore is very useful to monitor the digestion catalyzed by α-amylases exclusively. Similarly to PPA active site, three glycon and two aglycon binding sites are suggested for LDAmy based on the pattern of early hydrolysis products of BzG7PNP. The observed similarity between LDAmy and PPA raises the possibility of using known inhibitors of mammalian α-amylases to protect the potato plant from attack of Colorado potato beetle.

The results are presented of a survey of the resistance to acaricides of strains of economically important ticks from the cattle-raising areas of Kenya in 1970–75. Larval progeny of ticks collected in the field were subjected to an immersion test to determine their resistance status to toxaphene and dioxathion. The proportions of samples of the three major species shown to be resistant to or tolerant of toxaphene were Boophilus decoloratus (Koch) 99·3%, Rhipicephalus evertsi evertsi Neum. 77·3% and R. appendiculatus Neum. 62·5 %. A large proportion of the relatively few samples of R. pulchellus (Gerst.) were also resistant to toxaphene, but few resistant samples of Amblyomma variegatum (F.) and Haemaphysalis leachii leachii (Aud.) were collected, and only one sample of Hyalomma (H. marginatum rufipes Koch) was tolerant of toxaphene. None of these species was resistant to dioxathion. Organophosphorus resistance was noted in one species only, R. sanguineus (Latr.), collected from the suburbs of Nairobi.

The European cherry fruit fly, Rhagoletis cerasi (Diptera: Tephritidae), is a univoltine species that overwinters at pupal stage. Under optimum overwintering conditions pupae will develop into adults the next spring. Shorter or longer than optimum chilling periods induce prolonged pupae dormancy. Pupae that enter prolonged dormancy due to a short chilling period exhibit high emergence rates after a second cycle of cold/warm periods. Adults found to be larger and less fecund compared to their counterparts from pupae with annual diapause. On the other hand, extreme long chilling periods at pupal stage results in high mortality rates. However, for one Greek population, a substantial number of adults emerged following prolonged chilling of pupae (ca. 18 consecutive months). In this study, we used three R. cerasi populations in order to address possible geographical variation in fitness cost of adults from pupae with prolonged dormancy. In addition, the fitness traits of these adults emerging after prolonged pupae chilling were compared with that of their counterparts from pupae with annual diapause or prolonged dormancy. Our results reveal no population-specific variation in fitness cost of adults from pupae with prolonged dormancy. Within a population, lifetime fecundity did not differ between adults emerged from pupae with prolonged dormancy and those emerged after prolonged pupae chilling. Adults emerged from pupae exposed to prolonged chilling suffer an additional reduction in adult longevity compared to adults from pupae with prolonged dormancy. Hence, fitness of R. cerasi adults is regulated by diapause regimes of pupae.

Eristalinus aeneus (Scopoli, 1763) is a suitable candidate for artificial rearing due to its pollination efficiency and subcosmopolitan distribution. However, the high mortality found at the larval stage of this species needs to be overcome. In this research, two different larval media were used to study the life cycle of E. aeneus: brewery spent grain (BSG) from a local craft-beer factory and soaked oat grains (SOG). The age-stage, two-sex life table method was used to analyze the results, which were compared using the paired bootstrap test. The greatest mortality was found at the larval stage with both media. Individuals fed on SOG presented a shorter preadult developmental time (22.05 days) than those reared with BSG (26.97 days). This fact had a direct impact on the total preoviposition period, it being shorter with SOG (34.36 days) than BSG (38.29 days), although the second provided a larger total number of eggs (19,242 eggs) and a faster adult maturation (10.67 days). The population parameters indicated that both populations will display a positive growth under the studied conditions, being the mean generation time (T) significantly shorter when using SOG (38.71 days) than BSG (45.95 days). Despite the preadult results pointing to SOG being a more efficient medium, the promising fecundity values provided by BSG, as well as it's lower cost and ecological benefits, suggest that this second medium could be improved and used as an alternative to SOG in the near future.

Copidosoma graminis sp. n., a polyembryonic encyrtid parasitoid of armyworm pests of gramineous crops and pasture in Australia, is described and compared with related species. The parasitoid plays an important role in the natural control of these pests in Australia.

The greenbug, Schizaphis graminum (Rondani), is a major pest of cereals in some parts of the world and is of particular concern because it can be resistant to some insecticides and overcome the resistance of crops. In the UK, it has never been found on crops, but two rather little-known and closely-related species (Schizaphis holci and Schizaphis agrostis) are associated with the wild grasses, Holcus lanatus and Agrostis stolonifera. Since 1987, winged (alate) aphids morphologically resembling the greenbug have been found in increasing numbers in 12.2 m high suction-trap samples of the Rothamsted Insect Survey (RIS); hence, studies were undertaken to establish their identity. Clones (=asexual lineages) established from populations collected from H. lanatus in southern England showed strong preference for Holcus over Agrostis and Hordeum in laboratory tests and produced sexual morphs when transferred to short-day conditions, the males being apterous, as expected for S. holci. Multivariate morphometric comparisons of alatae caught in UK RIS suction traps in 2007 and 2011 with named specimens from museum collections, including S. graminum from many countries, indicated that the suction-trapped alatae were mostly S. agrostis and S. holci. Cytochrome c oxidase subunit I (COI) mtDNA obtained from 62 UK specimens from suction-traps had 95.4–100% sequence identity with US specimens of S. graminum. Two of the UK specimens had identical COI sequence to the US sorghum-adapted form of S. graminum, and these specimens also had 100% identity with a 640 bp fragment of nDNA CytC, indicating that this form of S. graminum may already be present in the UK. Present and future economic implications of these results are discussed.

Body size is an important life-history trait in eusocial insects which plays a key role in colony fitness. The division of labour, represented by caste polyethism, correlates with divergent morphological traits. Size polymorphism has been noted in the tropical fire ant, Solenopsis geminata; however, little is known regarding the differences in the size distributions of workers performing foraging tasks. In the present study, task partitioning was observed in the foraging activities of S. geminata. Two subgroups among foraging workers of S. geminata were discovered using the Gaussian mixture model: a large worker group (head width ≥ 0.924 mm) and a small worker group (head width < 0.924 mm). The foraging worker population comprised two distinct groups – 25.64% were large workers and 74.36% were small workers. Larger workers delivered heavier seeds faster than smaller workers, but this difference became less apparent when lighter seeds were being carried. When large prey such as crickets was encountered during foraging, S. geminata partitioned their tasks into cutting and transportation. The large workers were observed to cut cricket prey into fragments with their longer mandibles, and the small workers then transported these fragments back to the nest. These results present evidence of task partitioning among tropical fire ants, with different tasks being performed by ants of different castes.

The present paper, which is the last of the series, contains additional data obtained between November 1939 and December 1945.

In 1939, Helopeltis bergrothi, Reut., was found feeding on cacao pods and shoots at Owena by the writer; it was evident that this species was distinct from the cotton Helopeltis, which had been identified as bergrothi by the Imperial Institute of Entomology in 1924. The species attacking cotton is H. sanguineus, Popp., and this name should be substituted for bergrothi in the three papers on food-plants published in 1935, 1937 and 1940.

Sampling in Northumberland, England, and southern Scotland of pasture soils, the major larval habitat of Hydrotaea irritans (Fall.), showed larvel densities of between 0 and 30/m2; 15 different sites were examined, and all produced larvae. Larvae were found from September until June, larvael development continuing in the soil for about eight months. A study of the distribution within a single field that larvae were not confined to the wooded margins but occurred in significant numbers throughout the field. Higher numbers of larvae were present in the soil beneath cow pats than in the open field, but the proportion relative to the total population is small. Larvae prey was predominantly dipterous and coleopterous larvae. Pupation took place in the top 5 cm of pasture soil during May and lasted until late June. Emergence of adults took place from June until late July; males and females emerged over the same period