The taxonomy of African species of Antestiopsis, some of which are important pests of coffee, has hitherto been in confusion owing to the difficulty of finding decisive morphological characters. In the present study an attempt is made to clarify the relationships of the coffee pest species and some of their close allies by the use of both biological and morphological characters.

The species of Antestia and Antestiopsis occurring on coffee in Africa are differentiated in a key, and descriptions are given of the following: Antestiopsis orbitalis (Westw.), with three clearly distinguishable subspecies, orbitalis, bech-uana (Kirkaldy) and ghesquierei Carayon, several local colour forms of these, and a few variable populations that cannot be referred definitely to any one of the subspecies; A. intricata (Ghesq. & Carayon); A. facetoides sp.n. for the species hitherto known as “ faceta ” in eastern Kenya and Tanzania; A. crypta, sp.n. confined to Katanga; A. falsa (Schout.), a rare and imperfectly known species; A. lepelleyi sp.n., which does not feed on coffee; and A. littoralis sp.n., from the Kenya coast, known to the writer only from museum specimens.

Evidence for the arrangement adopted is discussed, and the taxonomic value of certain morphological characters is assessed. The distributions presented on maps are discussed, and it is concluded that the activities of man are unlikely to have obscured the natural patterns. A list is given of known host-plants, which, except for those of A. orbitalis orbitalis and form facetus, are with only a single other exception members of the Eubiaceae. The distribution on a local scale and recent changes of abundance of species in competition are discussed, and it is shown that A. orbitalis ghesquierei and A. o. bechuana appear to be spreading at the expense of A. intricata in Uganda and A. facetoides in Tanzania, respectively. Kesults of crossing East African species and forms show that those here regarded as species will not cross but that the subspecies of A. orbitalis will do so, producing intermediates that, when allowed to interbreed, are not as viable as pure strains. Finally an attempt to find morphometrical characters is discussed, and the results are given of a calculation of discriminant functions based on two characters. These, while, not conclusive, support the conclusions drawn from other evidence.

I remained in the proclaimed area till 6th August 1915, then returning to the vicinity of Monkey Bay for the purpose of endeavouring to establish artificial breeding places on a large scale.

While in the proclaimed area I took the opportunity of completing my survey of the distribution of Glossina morsitans, especially in the neighbourhood of Rifu and Kuti described by Dr. Shircore (Bull. Ent. Res., v, p. 87) as “primary centres 1 and 2,” which I had been unable to examine last season before the advent of the rains. As in the case of “ centres 3 and 4,” at Nyansato and Lingadzi respectively, I have not been able to find that the fly is sufficiently localised, even when the dry season is far advanced, as to render feasible any attempt to control it by prophylactic clearing of the bush. In the Rifu district there is a range of rocky hills and high ground running more or less parallel to the lake, with corresponding modification of the soil, so that a zone of scrub has sprung up, from half a mile to two miles in width, consisting very largely of thorn bush, among which are a few big trees. Towards the north this gradually dwindles, to be replaced by the borassus palms usually growing in the sandy ground along the Lake shore, and towards the south it gradually widens out and becomes continuous with the Kuti bush some five miles distant. Throughout its whole extent the fly was plentiful.

Laboratory spraying experiments were carried out with DDT, allethrin, the triethanolamine salt of 3:5 dinitrocresol (TDNOC) and HETP against eggs of different ages of Diataraxia oleracea (Lepidoptera) and with allethrin, HETP and TDNOC against eggs of different ages of Ephestia kühniella (Lepidoptera) and Dysdercus fasciatus (Hemiptera) under controlled temperature and humidity conditions.

During a large-scale air-spray trial using endosulfan against Glossina morsitans centralis Machado in the Okavango Delta area of Botswana, a programme of ageing all flies caught on fly-rounds was undertaken. The aim was to evaluate closely the effect of repeated sprays on the population and especially to determine the origin of the small residual population that often remains after spraying. Ageing males by the wing-fray method indicated that none survived the spraying. Ageing females by ovarian dissection showed that (a) no breeding occurred between sprays, (b) one pupal period was just covered by four spray applications, (c) the residual population was composed of females that had survived the spraying and (d) all survivors had been pregnant at the time of treatment. Dissections also showed a very low rate of insemination between sprays, but the few females that survived spraying were all inseminated. Larval and pupal periods under natural conditions of fluctuating temperature are discussed together with methods of improving air spraying results by eliminating pregnant females.

Arginine kinase (AK) is an important regulation factor of energy metabolism in invertebrate. An arginine kinase gene, named HaAK, was identified to be differentially expressed between Cry1Ac-susceptible (96S) and Cry1Ac-resistant (Bt-R) Helicoverpa armigera larvae using cDNA-amplification fragment length polymorphism analysis. The full-length open reading frame sequence of HaAK gene with 1068 bp was isolated from H. armigera. Quantitative reverse transcription polymerase chain reaction assay revealed that HaAK gene is specifically expressed in multiple tissues and at larval developmental stages. The peak expression level of HaAK was detected in the midgut of the fifth-instar larvae. Moreover, the expression of HaAK was obviously down-regulated in Bt-R larvae. We further constructed a dsRNA vector directly targeting HaAK and employed RNAi technology to control the larvae. The feeding bioassays showed that minute quantities of dsRNA could greatly increase the larval mortality and delay the larval pupation. Silencing of HaAK significantly retarded the larval development, indicating that HaAK is a potential target for RNA interference-based pest management.

Musca domestica L. (Diptera: Muscidae) is a vector of a range variety of pathogens infecting humans and animals. During a year, housefly experiences serial population bottlenecks resulted in reduction of genetic diversity. Population structure has also been subjected to different selection regimes created by insect control programs and pest management. Both environmental and genetic disturbances can affect developmental stability, which is often reflected in morphological traits as asymmetry. Since developmental stability is of great adaptive importance, the aim of this study was to examine fluctuating asymmetry (FA), as a measure of developmental instability, in both wild populations and laboratory colonies of M. domestica. The amount and pattern of wing shape FA was compared among samples within each of two groups (laboratory and wild) and between groups. Firstly, the amount of FA does not differ significantly among samples within the group and neither does it differ between groups. Regarding the mean shape of FA, contrary to non-significant difference within the wild population group and among some colonies, the significant difference between groups was found. These results suggest that the laboratory colonies and wild samples differ in buffering mechanisms to perturbations during development. Hence, inbreeding and stochastic processes, mechanisms dominating in the laboratory-bred samples contributed to significant changes in FA of wing shape. Secondly, general patterns of left–right displacements of landmarks across both studied sample groups are consistent. Observed consistent direction of FA implies high degrees of wing integration. Thus, our findings shed light on developmental buffering processes important for population persistence in the environmental change and genetic stress influence on M. domestica.

The physiological age of adult males of seven mealybug species was measured in relation to the elongation of the male pair of the waxy caudal filaments. These filaments begin to emerge after eclosion and reached their maximum length from 29.4–46.6 h. The studied males were divided into three age groups, expressed as percentages of the total waxy caudal filaments length. Attraction to a sex pheromone source was significantly higher in the oldest male group (maximum filaments growth) compared with youngest one. Only the oldest male group copulated successfully; few of the younger males tested displayed 'courtship' behavior towards conspecific virgin females. The calculated duration of the sexually active phase of the adult male life cycle varied among species ranging from 34.4 to 46.6 h. There were marked variations in the strength of attraction to a pheromone source according to time of day. There was a continuous decrease in sexual activity from morning to evening. Our findings reveal clear maturation periods for adult males of the seven studied species. The long immature phase of the adult male mealybug is probably also related to several physiological processes that are needed to complete male maturation. The most noticeable change is the elongation of the waxy caudal filaments. However, mating may be performed at any time ambient conditions are suitable. Whereas male mealybug flight towards a pheromone source is restricted to a few hours, the male may continue mating activity throughout its sexually active period.

Callosobruchus subinnotatus (Pic) is the major insect pest of stored bambara groundnuts, Vigna subterranea (L.) Verdcourt, in sub-Saharan West Africa, but little is currently known about its biology or how it may be controlled. A series of laboratory studies was performed to investigate the bionomics of and differences between two apparently different morphs of adult of each sex of this species, here termed ‘active’ and ‘normal’. Major differences in their morphology, physiology and behaviour were identified and are described in detail for the first time. They provide clear evidence of the existence of an adult polymorphism among populations of this species, which is comparable in certain respects to that previously described for C. maculatus (Fabricius) and C. chinensis Linnaeus. Adults can be separated into the correct morph based on characteristic differences in elytral and pygidial colour and pattern. ‘Normal’ adults are characterized by having high fecundity, short adult life and are relatively sedentary while ‘active’ adults exhibit reproductive diapause (suspension of reproductive activity), are long lived, and show (at least in females) increased dispersal tendencies. These characteristics suggest adaptation of the ‘active’and ‘normal’ morphs respectively to the different environments of field and seed stores, and the significance of the polymorphism in the life history of C. subinnotatus is discussed in this context. The design of any effective control regime for this bruchid needs to take account of and could potentially be based upon the existence of polymorphism in C. subinnotatus.

The following paper is intended only as a preliminary revision of this large and exceedingly important group of parasites, and it is the outcome of some six months' work on a small portion of the large mass of material awaiting identification in the collections of the British Museum and of the Imperial Bureau of Entomology. The writer not only has had access to all the types which he required to see that had been deposited in the British Museum, but also was so fortunate as to have been able to arrange with the authorities of both the United States National Museum and the National Hungarian Museum for exchanges of cotypes where sufficiently long series were available, and consequently has been able to examine and include in his key all, or the large majority of, the species that have been described from the Indo-Australian region by Continental and American writers. It should be placed on record that, in addition, the National Hungarian Museum, when not in a position to exchange cotypes, was so good as to forward to the writer on loan the types themselves. With all this extremely kind co-operation, therefore, it has been possible to make this paper tolerably complete; and for purposes of comparison it has been thought desirable to include in the key numerous Palaearctic and Ethiopian species, the types and cotypes of which are to be found in the British Museum.

The larvae of two species of swift moths, Hepialus humuli (L.) and H. lupulinus (L.), live in the soil and are common under grass in the British Isles, but do not usually have any obvious effect upon the grass. The larvae of H. humuli are polyphagous and when they occur under agricultural or horticultural crops they may cause damage by feeding on the roots. Lettuce, strawberry and chrysanthemum are most frequently damaged.

The adults, which are described, fly at dusk, the female seeking the male. The female lays between 200 and 1,600 eggs, with a mean of about 600, over a period of four days. Sweep-net catches showed the ratio of the sexes to be approximately equal, and mercury-vapour light-trap catches showed that the flight period in southern England is principally in June.

In the laboratory, never less than 80 per cent, of eggs hatched, even in dry air, and the shortest incubation period, between 11 and 24 (mean 18) days, was at 20°C. At 5°C. they did not hatch, but remained viable for at least six months.

The larvae were reared in small cells drilled in blocks of plaster of Paris, which were stood in a tray of water, or in vials containing a layer of moist plaster of Paris, and were fed on pieces of carrot.

The growth of the larval head capsules was geometric and allowed 12 instars to be distinguished at 15°C.; at higher temperatures there may be more.

The growth curve of the larvae was S-shaped with a very distinct fall in weight in each instar for several days before moulting. The daily intake of food was weighed, and the conversion rate shown to be small, ranging from 0·00058 to 0·04, as compared with 0·205 to 0·49 recorded for other Lepidopterous larvae.

At 5°C., larvae did not develop beyond the second instar, nor beyond the fourth at 10°C. The optimum temperature for their development (mean period 224 days) was 15°C., although mortality was high. They developed at 20°C. more rapidly (mean 197 days) but more died. Larvae kept in a container sunk in the soil outdoors developed more slowly than those at 15°C. and had only reached the eighth instar by February (239 days after hatching). This evidence, together with that from an artificially infested plot in the field and general field observations, suggests that the usual life-cycle lasts two years.

The responses of females of Aëdes aegypti (L.) to beef blood have been investigated. Paired comparisons were made of the numbers of mosquitos attracted to test and control materials.

Vapours emanating from the heparinised blood were found to be significantly more attractive than water vapour in an olfactometer. When the blood vapour was passed through an aqueous solution of Ba(OH)2 this attractiveness disappeared.

Exposure of heparinised blood on filter paper proved it to be two to four times as attractive as water or washed corpuscles suspended in saline. Plasma proved to be 4·7 times as attractive as water, indicating that the attraction of blood lies entirely in the plasma.

Treatment of blood with BaCl2 and a vacuum, thus rendering it incapable of evolving CO2, removed its attractiveness to mosquitos. Treatment with vacuum alone, which may be expected to remove the volatile substances, did not completely remove the attractiveness; nor did the treatment with BaCl2 alone, which removes the bicarbonates in the blood.

The attractiveness of blood was completely removed by desiccation and was not returned by remoistening. No attractive substance was isolated in an ether extract of blood.

When CO2-freed blood was treated with gaseous CO2 its attractiveness was significantly increased. When the treatment was such as to restore the normal CO2-producing capacity, the attractiveness was one-half that of whole blood. The attractiveness of whole blood was not increased by adding excess CO2.

It is concluded that the CO2 in beef blood is a definite element in its attractiveness, though probably not the most important one.

Records were kept of the catches of tsetse fly by three types of traps, the Langridge box screen, the Swynnerton awning screen, and a modification of the latter incorporating a screen skirt, in the South Busoga fly-belt, Uganda, where Glossina pallidipes Aust., G. fuscipes Newst. and G. brevipalpis Newst. are abundant. Only two specimens of G. brevipalpis, but large numbers of the other two species, were caught, by far the largest catches being obtained by the awning screen-skirt trap.

Little is needed by way of introduction, beyond the statement that this paper is really a continuation of a previous one (“The African Species of Culex and allied Genera,” Bull. Ent. Res., Oct. 1911, pp. 241–268). In the present paper a complete synopsis is given of all the African species, with the exception of some of those already tabulated and of the genus Anopheles and its sub-divisions. Through the kindness of Prof. R. Newstead, the author has now been able to examine the types in the collection of the Liverpool School of Tropical Medicine, so that the number of undetermined species has been considerably reduced, and all have now been accounted for except those given as doubtful in the paper referred to.

Time/mortality studies with Carabidae exposed to thionazin, phorate, disulfoton and menazon in an acid sandy loam soil were done in controlled laboratory conditions. Carabids were killed by soil treated with thionazin within dosage rates normally required for satisfactory control of nematode or insect pests of crops, i.e., 2·24–8·96 kg/ha, but menazon was virtually non-toxic. Soil moisture increased the speed of kill of Carabidae in thionazin-treated soil presumably by affecting processes of adsorption and desorption of the pesticide to soil colloids and by influencing burrowing behaviour. The speed of kill increased with a rise in temperature, mortalities occurring 2·2 × faster at 10°C, 8·1 × faster at 15°C and 11·8 × faster at 22°C than at 7°C, but was decreased by illumination which decreased the activity of the nocturnal Carabids. The addition of calcium carbonate to increase soil pH did not alter immediate mortality by thionazin but persistence was decreased. Speed of kill was negatively correlated with adult size of Carabid species that behaved similarly, small species such as Bembidion lampros (Hbst.) (mean weight 2·1–2·2 mg) dying 12–13 × faster than female adults of Pterostichus vulgaris (L.) (mean weight 195 mg). Species which burrowed in soil were more susceptible than those which did not, as were newly moulted or starved adults. At 15°C and in wet conditions the “ half-life ” of thionazin based on speed of kill in a soil of pH 6·1–6·7 was 1–2 weeks but when determined by gas-liquid chromatography was 3–4 weeks at 22°C. Leaching could account for the loss of up to 12% of thionazin from the top 9 cm of soil.

Most trapping techniques for estimating populations assume that all individuals are equally trappable. Where potential protein sources are used as baits for muscoid flies, which are known to have a cyclical intake of protein during ovarian development, numbers caught may not be comparable. Accumulated field data on the reproductive stages of samples of the bushfly (Musca vetustissima Wlk.) in a study area near Canberra have been analysed to show that only flies in the last stages of maturing their eggs (reproductive stage IV) are uniformly under-represented (about 22% of expectation) in baited samples.

Although apomixis is the most common form of parthenogenesis in diplodiploid arthropods, it is uncommon in the haplodiploid insect order Hymenoptera. We found a new type of spontaneous apomixis in the Hymenoptera, completely lacking meiosis and the expulsion of polar bodies in egg maturation division, on the thelytokous strain of a parasitoid wasp Meteorus pulchricornis (Wesmael) (Braconidae, Euphorinae) on pest lepidopteran larvae Spodoptera litura (Fabricius) (Noctuidae). The absence of the meiotic process was consistent with a non-segregation pattern in the offspring of heterozygous females, and no positive evidence was obtained for the induction of thelytoky by any bacterial symbionts. We discuss the conditions that enable the occurrence of such rare cases of apomictic thelytoky in the Hymenoptera, suggesting the significance of fixed heterosis caused by hybridization or polyploidization, symbiosis with bacterial agents, and occasional sex. Our finding will encourage further genetic studies on parasitoid wasps to use asexual lines more wisely for biological control.

The cassava green mite, Mononychellus tanajoa (Bondar), is an exotic pest in Africa and is the target of a classical biological control programme. Field data from the Neotropics, where it is indigenous, are presented for the first time, charting the variation in abundance of M. tanajoa over several seasons. This was highly variable, with a characteristic trough mid-year and a peak at the turn of the year. This pattern corresponded positively with rainfall levels, appearing to fit a phenology also characteristic of African studies, where rainfall at the start of the wet season promotes a leaf flush and so growth in M. tanajoa populations. Analyses implied some impact of leaf-inhabiting predatory mites (predominantly Neoseiulus idaeusDenmark & Muma) and a considerable impact of the fungal pathogen Neozygites floridana Fisher on M. tanajoa populations. This pathogen was not observed in the host population for several (generally dry) periods implying survival outside the host, perhaps as resting spores. This is a particularly desirable characteristic of a biological control agent. It is therefore proposed that N. floridanamight be of particular use in drier cassava-growing areas where rainfall at the outset of the wet season is not sufficiently intense to cause heavy M. tanajoa mortality but may be sufficient to stimulate epizootics of the fungal pathogen, protecting the flush of new cassava growth.

1. An ecological description of the Red Sea coast of the Anglo-Egyptian Sudan is given, with special reference to the occurrence of the solitary phase of Schistocerca gregaria in its different parts and zones.

2. The greatest numbers of solitary Desert locusts were found amongst raingrown dukhn (Pennisetum typhoideum, Rich.) cultivated in the Suaeda belt of the coast, near the sea.

3. The factors responsible for the higher population of solitary locusts among the cultivation are probably the soil consisting of soft loose sand, and the more or less evergreen condition of the weeds on cultivated plots. It appears possible, however, that in some localities with naturally loose sandy soil all areas suitable for vegetation are cultivated, and in this case the cultivation in itself is not of primary importance.

4. Incipient outbreaks were observed in the type of cultivated areas described above in 1933–34, and again in 1934–35 winter seasons. Hoppers of the phase congregans were found mostly on a weed, Heliotropium undulatum, which is preferred by young hoppers to other food-plants, and seemed to act as a concentrating factor for the hoppers. No hoppers of the ph. congregans were found on clean cultivation where this weed was absent.

5. The chief factor determining the commencement of an outbreak seems to be heavy winter rains (over 240 mm. during the season), starting early (end of October) and continuing late (end of February), which allows for the development of two successive winter generations, as follows:—(a) Early maturation of old adults (November); (b) plentiful oviposition of old adults (November-December); (c) hoppers beginning to emerge (end of November); (d) hoppers beginning to become adult (early January); (e) majority of hoppers adult (end January); (f) these young adults remaining among dukhn in a fairly crowded condition (February); (g) young adults maturing (end February); (h) young adults ovipositing (March); (i) hoppers hatching (end of March-April); (j) young hoppers crowded on Heliotropium, assuming congregans coloration and later forming marching bands (April); (k) emigration of young flying swarms (May).

6. The exact cause of the rapid maturation of young adults of the first winter generation has not been discovered, although a short period of very high humidity seems to have some effect. There is no doubt that late rains are necessary for most adults to mature and oviposit in the field.

7. The Red Sea coast of the Sudan is distinguished from the interior of that country by its higher air humidity, by winter rains, and by the fact that the rainy season can extend for a longer time than the summer rainy period inland. The northern parts of the coast, north of the latitude 20°N., are less likely to produce outbreaks only because heavy and prolonged rains are unlikely to occur there.

8. General conditions in Eritrea, south of the Sudanese border, are such that some outbreak areas should be expected to exist there.

9. It appears probable that the Arabian coast of the Red Sea also contains some outbreak areas. As regards inland parts of Arabia, their climate, the distribution and the life-cycle of the solitary locusts there, are too little known to estimate the possibility of the existence of outbreak areas, until a special investigation is made.

10. The results of the investigations on the Red Sea coast put under suspicion of harbouring outbreak areas of the Desert locust all those parts of the sea-coasts of Africa and Asia which may obtain in some years winter rainfall of not less than 240 mm. extending for a period sufficiently long to allow for the development of two successive winter generations of the locust.

The earthworm, Lumbricus rubellus, plays an essential role in soil ecosystems as it affects organic matter decomposition and nutrient cycling. By ingesting a mixture of organic and mineral material, a variety of bacteria and fungi are carried to the intestinal tract of the earthworm. To get a better understanding of the interactions between L. rubellus and the microorganisms ingested, this study tried to reveal if the diet affects the composition of the gut microflora of L. rubellus or if its intestinal tract hosts an indigenous, species-specific microbiota. A feeding experiment with L. rubellus was set up; individuals were collected in the field, transferred to a climate chamber and fed with food sources of different quality (dwarf shrub litter, grass litter or horse dung) for six weeks. DNA was extracted from the guts of the earthworms, as well as from the food sources and the surrounding soil, and further analysed by a molecular fingerprinting method, PCR-DGGE (Polymerase Chain Reaction – Denaturing Gradient Gel Electrophoresis). We were able to demonstrate that the gut microbiota was strongly influenced by the food source ingested and was considerably different to that of the surrounding soil. Sequencing of dominant bands of the bacterial DGGE fingerprints revealed a strong occurrence of y-Proteobacteria in all gut samples, independent of the food source. A specific microflora in the intestinal tract of L. rubellus, robust against diet changes, could not be found.

During the summer of 1956, a quantitative study of a field population of Wheat Bulb Fly, Leptohylemyia coarctata (Fall.), was carried out at Rothamsted.

The work consisted principally of a study of the development and decline of a population of adult flies. This was supplemented by observations on the populations of the immature stages.

Emergence was investigated by the use of a cage of fine terylene netting, 24 ft. long, 12 ft. wide, and 6 ft. high. This was erected in an infested wheat field shortly before flies were expected to appear, and was searched twice daily, at 10 a.m. and shortly before sunset.

A total of 293 male flies was caught during the 26 days from 24th June to 19th July. Of these, 186 appeared between 1st and 6th July. The highest day's catch was 40 flies on 6th July, by which date (inclusive) about 84 per cent, of the final total had emerged.

A total of 258 female flies was caught during the 35 days from 21st June to 25th July. Of these, about half emerged between 6th and 10th July. The highest day's catch was 37 flies on 8th, by which date (inclusive) 66 per cent, of the final total had emerged.

Population decrease was investigated by the method of marking and recapture. The newly emerged flies caught in the cage were marked with Artist's oil colours and released in the cage. The colour of the mark was changed daily so that the age of marked flies could be ascertained. A search was made for marked flies every three days and their numbers, marks and sex were recorded. From the recapture figures, estimates of the numbers of flies surviving at different times after marking were obtained. Mortality during the first day was very high, but after this numbers decreased at a steady rate. This initial high mortality was believed to be due to marking. The length of life of marked flies which survived this immediate effect was, however, not impaired, therefore the rate of population decrease was estimated from the recapture figures alone, that is, without reference to the numbers originally marked. The half-life of male and female populations was estimated as 7·3 and 11·1 days, respectively.

Application of the estimated rate of population decrease to the observed emergence figures enabled a general picture of the size and structure of the population to be obtained. The predominance of males over females during the early part of the season and the later predominance of females over males were explained.

Observations on the populations of the various stages showed that the mortality between pupation and maturation of adults was high, and that the egg populations inside the cage during the autumn of 1956 was only about 1/7th of that of the previous year. This reduction was not observed outside the cage and may have been due to the survival rate and fecundity of the flies being affected by the experiment. Further work will be necessary before this can be elucidated.