Published records and recent unpublished field observations on Trox procerus Har. in Asia and Africa are assembled. All stages of the life-cycle are figured, and brief descriptive notes on the egg, larval and pupal stages, are given. It is pointed out that the egg and larval stages have only been recorded from egg-fields of the Desert Locust, Schistocerca gregaria (Forsk.), and that the larvae feed on the eggs of the locust, sometimes causing considerable mortality. In contrast, the adults appear to survive independently of the locust, and it is suggested that the apparent concentration of adults of T. procerus in areas where Desert Locusts are ovipositing is due to their being attracted to the numerous dead locusts that are present in such areas.

Helopeltis pernicialis, a new species of bryocorine Miridae, is described from northern Australia, where it has become established as a serious pest of cultivated cashews, Anacardium occidentale (Anacardiaceae). Information on the biology and pest status of the bug is provided from studies conducted near Darwin, Northern Territory.

The taro-feeding delphacid genus Tarophagus is revised. Three species are recognized: T. colocasiae (Matsumura) stat. rev. & comb. n. with which T. proserpina taiwanensis Wilson is synonymized; T. persephone (Kirkaldy) with which T. proserpinoides (Muir) and T. proserpina australis Fennah are synonymized; and T. prosperpina (Kirkaldy). The three species are separated by characters of the male and female genitalia, and each has a different distribution in Asia and the Pacific. Only in Papua New Guinea are all three species sympatric. Earlier studies on biology and pest status are reviewed in the light of these investigations.

Static tethered flight was used under laboratory conditions to investigate the flight duration of Chilo partellus (Swinhoe). A flight mill was used to measure flight velocity. Mated females flew for a longer time than unmated ones. Females also flew for a longer time than males. Mated females were able to fly and lay eggs alternately for at least three nights in a row. Flight did not affect the number of eggs deposited by females. The results from the flight mill show that the mill is an accurate device to measure flight velocity. The airspeed of C. partellus proved to be 0.9 m/s, and there appeared to be no difference between the flight velocity of mated or unmated males and females.

The object of the work described in this paper was to compare adults of Oryzaephilus surinamensis (L.) and O. mercator (Fauv.) by morphological and biometric methods with a view to determining the status of the latter as either a variety of O. surinamensis or as a separate species.

There are some marked and constant differences between the two insects in the structure of the male genitalia. These are listed.

The analysis of the biometric results shows a clear-cut difference between the two insects in the ratio of eye length to temple length. All the other ratios considered overlap, although the means may be widely different. Some of these ratios are illustrated by histograms.

A cross-breeding experiment gave no offspring from the mixed pairs.

It is concluded that O. mercator is a good species which can be recognised morphologically.

During six years medical work in the northern provinces of Nigeria I have caught and examined every morning all the mosquitos I could find in my own bungalow. I have done this with a view to finding out which are the common domestic species in this region of West Africa, and their seasonal variation throughout the year.

A pyralid moth belonging to the Marasmia generic complex of leaf-rolling defoliators of rice in S.E. Asia is described and named M. patnalis sp. n. It is differentiated from M. bilinealis (Hmps.), M. ruralis (Wlk.), M. suspicalis (Wlk.) and Cnaphalocrocis medinalis (Gn.), with which it had previously been confused because of similarity of the adults and shared host-plant association.

An arsenic-resistant tick was first noticed in the East London district of South Africa in 1938–39. It was a strain of the one host blue tick, B. decoloratus. BHC was very toxic to the tick, as 50 p.p.m. of the gamma isomer killed adult females in in vitro experiments. Field results in 1946–47 were equally convincing. Weekly dippings in BHC washes containing 50 p.p.m. gamma isomer brought the arsenicresistant tick under control.

In March 1948, BHC was found to be ineffective against blue ticks at “Burnside”, “Mistley” and “Gulu”, farms in the East London district. Later, ticks at “Tharfield” and “Elmhirst” in the Bathurst area survived regular weekly dippings in BHC preparations. In vitro experiments showed that adult female blue ticks taken from these localities could withstand high concentrations of gamma BHC, while females of the same species from other areas were readily killed. Not even 1,000 p.p.m. would give 100 per cent. control of ticks from resistant areas, and different sources of gamma BHC were equally ineffective. Laboratory experiments further indicated that the ticks were still arsenic-resistant. Indeed arsenic resistance appears to be associated with BHC resistance, as no BHC-resistant tick has been found that is not arsenic-resistant. The chlorinated cyclic hydrocarbons toxaphene and chlordane were ineffective against BHC-resistant ticks, but controlled BHC-sensitive ticks in the laboratory. DDT gave moderate in vitro results against both resistant and sensitive ticks.

(1) An extensive survey covering a period of 18 months was carried out in Zanzibar, Algeria, Morocco and some parts of France with a view to obtaining parasites of white grubs for furthering the control of Phytalus smithi, Arrow, in Mauritius.

(2) In Zanzibar the results of the survey showed that white grubs are of no great economic importance in clove plantations in this Island. Larvae of several species of white grubs were obtained, viz.: Entyposis impressa, Kolbe, Schizonycha spp., Anomala delagoa, Pèr., etc. ; these larvae are parasitised by the Dexiid fly, Microphthalma disjunctum, Wied. The percentage of parasitism at the time of the survey was from 0·10 to 0·53 per cent. Scoliids were not in great number ; the parasitism amounted to 0·6 per cent. Parasites of adult beetles were obtained on the following insects: Entyposis impressa, Kolbe, Schizonycha spp. and Anomala plebejus, Ol., the parasites being Pexopsis pyrrhaspis, Villen., and an Adapsilia, not yet determined. The parasitism on the above mentioned beetles varied from 1 to 9·7 per cent.

The Ceratitis FAR complex (Diptera, Tephritidae) includes four economically important frugivorous flies (Ceratitis anonae, Ceratitis fasciventris, Ceratitis quilicii, Ceratitis rosa) whose immature stages and adult females cannot be properly resolved through morphological identification. In order to develop a simplified molecular tool for the identification of two of these species (C. rosa, C. quilicii), we selected a subset of six microsatellite markers out of a panel of 16 loci that were previously developed for the molecular differentiation of the taxa within the complex. These six markers were first tested in silico and then used for the actual genotyping of C. quilicii and C. rosa, resulting in the correct identification of all male reference specimens. Here, we propose an integrated morphological and molecular setup for the identification of the four species of the FAR complex. The decision map relies on preliminary DNA barcoding or morphological identification (when possible) to exclude species not belonging to the complex followed by (a) morphological identification of all adult male specimens and female C. anonae, (b) molecular identification via a panel of 16 microsatellite markers for immature stages, damaged vouchers and samples potentially including adult female C. fasciventris/C. quilicii/C. rosa and (c) molecular identification via a reduced panel of six microsatellite markers for samples including only C. quilicii and C. rosa. This simplified diagnostic setup was profitably implemented in the framework of the ERAfrica fruit fly project and will help correctly identify species within the FAR complex for their early detection and monitoring.

Of all the measures designed to effect a reduction in the number of mosquitos “ oiling,” or the application of kerosene in one form or another to collections of water in the neighbourhood, is I suppose the favourite. The popularity of this measure is no doubt an indication of its general efficiency, and as it is a remedy that can and should be employed by the individual as well as by the Sanitary Authorities, it has become familiar to every dweller in the tropics. This familiarity has, I believe, led to an exaggerated confidence in its efficacy.

Gravid females of the red locust, Nomadacris septemlasciata (Serv.), were initially influenced by the microclimate in the selection of oviposition sites, and a laboratory investigation showed that females preferred to lay in well-illuminated areas with a soil temperature between 43 and 37°C., and avoided areas of very high surface humidity. Final acceptance of the soil took place only after the locust had probed with its ovipositor, and experiments demonstrated that particle size, compaction, moisture content and chemical composition of the soil all influenced the choice of oviposition site, while pH did not.

Temephos resistance in savanna cytospecies of Simulium damnosum Theobald s.l. and the forest cytospecies S. sanctipauli Vajime & Dunbar, from West Africa is correlated with an increase in general esterase activity. Metabolism studies indicated that esterase products were the major metabolities in both forest and savanna resistant strains of S. damnosum s.l. compared to the susceptibles. In the presence of an esterase synergist, a large amount of the oxon analogue of temephos was produced by the resistant forest cytospecies S. sanctipauli. This strain is also resistant to chlorphoxim, and it is likely that the increase in oxidative activity observed is connected with the chlorphoxim rather than the temephos resistance. There was no evidence of glutathione transferase-, oxidase- or acetylcholinesterase-based temephos resistance machanisms in the savanna species of S. damnosum s.l.

The following report is the fourth of a series dealing with the blood-sucking insects which are or may be implicated in the transmission of disease in man and other animals. The previous reports have appeared in different issues of this Bulletin* and should be consulted in conjunction with this, as many aspects of a general character, which are equally applicable to all West African Colonies, have been discussed there and need not therefore be reiterated here.

Helicoverpa armigera is a significant agricultural pest and particularly notorious for its resistance to many types of common insecticides. RNA interference (RNAi) is a mechanism of post-transcriptional gene silencing and trigged by double-strand RNA (dsRNA), has become a widely used reverse genetics and potent tool for insect pest control. In this study, the effect of ingestion and injection delivery methods of dsRNA related two important enzyme genes, α-amylase (HaAMY48, Ha-AMY49) and juvenile hormone esterase (Ha-JHE), were examined on growth and development of H. armigera. After 24, 48, 72 and 96 h of feeding bioassay, significant down regulation was observed about; 56, 68, 78, 80.75% for HaAMY48, 60, 70, 86.5 and 96.75%, for Ha-AMY49 and 14, 27.5, 23 and 31.7% for Ha-JHE, respectively. The results for injection assay was 61.5, 71.5, 74 and 95.8% for Ha-AMY48; 70, 88, 91.5 and 97.7% for Ha-AMY49 and 22, 61, 75 and 74% for Ha-JHE after 24, 48 and 72 h of last injecting, respectively. Larvae that treated with dsRNA, fed or injected, lost more than half of their weight. 50% mortality in treated larvae was observed in the case injection bioassay with dsHa-JHE and 59% of larvae that fed of dsRNA-treated cubes survived. DsHa-AMY48 and 49 have significant mortality, but mixing of them is more effective in both bioassays. Injection bioassay has a potent inhibitory effect on α-amylase-specific activity about more than 87% in treated larvae with mix of dsHa-AMY48 and 49. Adult malformation percent was evaluated for feeding (28, 35.5 and 43% for Ha-AMY48, 49 and Ha-JHE, respectively) and injection bioassay (23, 42 and 29% for Ha-AMY48, 49 and Ha-JHE, respectively). All these finding suggest that Ha-AMY48, Ha-AMY49 and Ha-JHE can be new candidates to scheming effective dsRNAs pesticide for H. armigera control.

Aphids perform a series of behaviours to assess feeding suitability and, hence, to select a plant. Little information, however, is available on such behaviour after aphids have settled on a plant. Observation of probing behaviour over an extended period of time can improve our understanding of insect-plant interactions and is instrumental in the study of crop resistance. Here, we assessed the influence of aphid age and plant resistance level on aphid behaviour. An electrical penetration graph (EPG) technique was implemented to monitor the behaviour of potato aphid, Macrosiphum euphorbiae, alates on potato, Solanum tuberosum, and on both a susceptible and a resistant genotype of a wild Solanum species, S. chomatophilum. The behaviour was measured at daily intervals for the first seven days following adult emergence. The results indicated independent and interacting effects of aphid age and plant genotype on probing behaviour. Some behavioural discrepancies between susceptible and resistant genotypes were only observed after the first day, thus highlighting the limits of punctual one-day behavioural studies to assess plant resistance mechanisms. Our work supports the hypothesis that aphids continuously adapt their behaviour to the plant characteristics.

Anastrepha fraterculus (Wiedemann), a pest of great economic importance in South America, needs urgently to be controlled by environmentally friendly methods such as the sterile insect technique for which mass rearing of insects is required. Because oogenesis takes place during the adult stage, mass-rearing facilities should provide the females a diet that maximizes egg production at the lowest cost. Accordingly, we investigated the effect of artificial protein sources in the adult diet (yeast derivatives of different cost but with similar amino acids profiles, and the addition of wheat germ) on fecundity. Additionally, we evaluated different ratios of yeast derivatives or wheat germ on ovary maturation, fecundity, and fertility as well as their association with the nutrient content of females. Females fed hydrolyzed yeast and yeast extract attained the highest fecundity level, and those fed brewer's yeast the lowest. Reducing the amount of hydrolyzed yeast, an expensive protein source, in the diet negatively affected fecundity and ovary maturation. Increasing the amount of brewer's yeast, a low-cost protein source, did not favor fecundity. The addition of wheat germ in the adult diet improved fecundity regardless of the yeast derivate considered. Percentage of egg hatch was not affected by the diet. Nutrient content of A. fraterculus females varied according to the adult diet provided and mating status. Our findings provide novel baseline information to understand the role of nutrition on reproductive performance of A. fraterculus females and are discussed in the context of resource allocation. They also provide valuable advances in the search for cost-effective adult diets at fruit fly mass rearing facilities.

The present research was carried out in the Department of Agricultural Entomology at Manchester University, under the direction of Dr. A. D. Imms. I am greatly indebted to him both for giving me the insects upon which this research was prosecuted, and also for much help at the University, and afterwards in looking over my paper and aiding its publication.

The European fruit lecanium (EFL), Parthenolecanium corni Bouché (Hemiptera: Coccoidea), is a common and harmful soft scale, which attacks Fraxinus oxycarpa Willd. and other ornamental and orchard plants in Tbilisi, Georgia. This study investigates the phenology, degree of plant damage and effect of parasitoids on this scale in Tbilisi, a densely populated area. We present data on the 32 species of chalcidoid parasitoids recorded from EFL in Georgia and south-eastern Europe. The scale is heavily parasitized in Tbilisi, but we did not find any variation in seasonal abundance. The most common parasitoid of EFL was Blastothrix longipennis (Hymenoptera: Encyrtidae).

Sufficient pupae of G. pallidipes Aust. for testing were available from the Zambezi valley only between September and early November and were of all ages. These pupae or the adult fly were exposed to gamma-radiation from a 60Co source at rates between 54 and 122 rads per min., and reproduction and mortality were studied by described procedures.

Effective pupal mortality due to radiation increased, and the proportion of males among the viable emerging flies decreased, with dosage between 4,000 and 16,000 rads. Eeproduction and survival of adult males emerging from treated pupae decreased with an increase in dosage and a decrease in pupal age at the time of treatment. Irradiation of adult males within three days of emergence produced slightly lower levels of sterility and similar survivals. Complete male sterility was rarely obtained with any of the treatments, though all the females, with one exception, were sterilised from 4,000 rads upwards, but the flies were fully competitive with untreated males and reduced reproduction below expected values. Treated males were fully capable of inseminating female flies and the sperm was motile and apparently behaved normally. Dominant lethality in the males appeared to be expressed by the failure to produce pupae and in the females by the complete failure of oogenesis.