Ten fertilised female Glossina austeni Newst. reared from pupae with a weight range of 17–33 mg were maintained singly in small cages, and were offered food six days per week. The mean data for the flies were 151 days life span, 14–5 pupae per female and 25–4 mg pupal weight. One fly showed an abnormal digestive condition, and several failed to larviposit at the end of a cycle. The weight of pupae produced was related to the total amount of blood ingested in each normal cycle. A comparison between fertilised and virgin flies indicated that 50% of the blood ingested by the former was for pupal production. Large flies took larger blood-meals and fed less frequently than small flies.

The author discusses the restriction of the genus Lepidosaphes to nine Holarctic species by Borchsenius and his assignment to other genera of most species previously placed in Lepidosaphes. These changes in generic assignment have affected the names of many species of economic importance. A key is presented to 13 genera allied to Lepidosaphes.

Twelve Trichogramma spp. are redescribed. These are: T. australicum Girault, T. dendrolimi Matsumura, T. euproctidis (Girault), T. evanescens Westwood, T. fasciatum(Perkins), T. japonicum Ashmead, T. minutum Riley, T. perkinsi Girault, T. pretiosum Riley, T. retorridum (Girault), T. semblidis (Aurivillius) and T. semifumatum(Perkins). Differences in male genitalia are emphasised, being most stable and reliable, and pigmentation as well as wing and antennal trichiation are described, being characters of supplementary importance for species diagnosis. Host and distribution records are also given. In the male genitalia, the shape of the dorsal expansion of the gonobase differs considerably in some species and the position of the chelate structures with respect to the tips of the gonoforceps also varies; the median ventral projection is large in some species, reduced in some and almost absent in others. A comparative account of the most distinguishing characters of the different species is included and a key to 15 species is provided

A panteles flavipes (Cam.) and A. sesamiae Cam. are important parasites of graminaceous borers in the Oriental and Ethiopian Regions, respectively. Both have been utilised for biological control. A. sesamiae has become the commonest parasite of Sesamia calamistis Hmps. in Mauritius (Anon., 1954), while A. flavipes has become remarkably successful against Diatraea saccharalis (F.) in Barbados (Simmonds, 1969a). In view of the interest engendered in these parasites, particularly the latter, by these successes, a general account is presented here of their biology, based on published data and on the author's observations at the East African Station (Kawanda, Uganda) of the Commonwealth Institute of Biological Control.

Cotton stainers (Dysdercus spp.) are members of the family Pyrrhocoridae and many are pests of cotton throughout the tropics. Ten species are found in Africa (Pearson, 1958). Three of these have been established in colonies at Arusha, Tanzania. They are D. cardinalis Gerst., D. fasciatus Sign. and D. nigrofasciatus Stål.

Williams (1960) suggested the use of insect hormones as possible pest control agents. Hormones are internal secretions that regulate a wide variety of physiological processes especially those concerned with growth, development and egg maturation (Novék, 1966). Similar activity has been reported for a series of compounds related to insect hormones and known as juvenile hormone mimics or analogues (see reviews by Berkoff, 1969; El-Ibrashy, 1970; Ellis et al., 1970; Wigglesworth, 1970). This paper presents the results of a laboratory investigation using one such hormone analogue, methyl farnesoate dihydrochioride (DMF) prepared according to methods described by Law et al. (1966) and Romaňuk et al. (1967) when applied to the cotton stainer bug Dysdercus fasciatus Say.

In Leptohylemyia coarctata (Fall.) the germarium cuts off oocytes which develop through the stages 00 and 0 and I-V, recognised in other Cyclorraphous flies, in 4–5 weeks. All eggs of one batch of the gonadotrophic cycle ripen at the same time. After oviposition, the split intima, the remains of the follicular epithelium, and the nurse cells slowly contract to form the follicular relic. Flies swept from winter wheat during June and July and caught in water traps in July and August showed all stages of egg development. In 1970, 24·7% of the females swept from the crop had completed the first, 4–7% the second and 0–4% the third gonadotrophic cycle. All the eggs were not laid at the same time. During later gonadotrophic cycles, some ovarioles were non-functional. Flies laid one or two batches of eggs, rarely three. In 1970, many flies were attacked and killed by E. muscae. Only one out of 115 newly emerged female wheat bulb flies presented with foods usually found in the crop or citrated blood contained mature eggs after 24–27 days in small cages. Those fed only on 0·1 M glucose survived but did not deposit yolk in the ovum; those provided only with yeast paste died. Honey dew from cereal aphids was the main source of sugar. Water in droplet form and space to move seem necessary for the maturation of the eggs.

During 1963–69 the United States Department of Agriculture sponsored investigations on scale insects and their natural enemies in West Pakistan.* In the course of the survey Lepidosaphes conchiformis (Gmel.)† was collected from several localities. It occurred sporadically, but infestations were heavy on most of the plants on which it was found. In the hills it was commonly parasitised by Aphytis maculicornis (Masi). The potential importance of the scale and its parasite merited laboratory studies at Rawalpindi.

Laboratory investigations of olfactory perception in the tsetse fly Glossina morsitans orientalis Vanderplank, were carried out by measuring the modulation of the spontaneous rate of activity by sudden olfactory stimulation. Marked responses were obtained to emanations from guinea-pig, chick, crocodile and the human hand and forearm. Emanations from human skin despite the absence of expired carbon dioxide induced a strong response compared to the other host types. The stimulus was removed by rinsing the skin with acetone solvent. Air passed over material impregnated with human sweat and odour was ineffective. Responses to guinea-pig odour and guinea-pig expired air were approximately equal. Carbon dioxide was the important factor in expired air. The quantitative relationship between stimulus and response was non-linear, responses increasing with approximately exponential increases in stimulus intensity. The existence of an airborne sexual stimulus could not be demonstrated.

Adults of Aphis fabae Scop. can weigh from as little as 200 μg to as much as 1 800 μg (Way & Banks, 1967), a remarkable range in size for a single species. An extensive range in size also occurs among the adults in other species of aphid (Murdie, 1969a, b; Dixon, 1970). Small individuals result when aphids develop either under crowded conditions or on a mature host-plant; large aphids result when the nymphs are reared in isolation or on young or senescent host-plants (Way & Banks, 1967; Murdie, 1969a, b; Dixon, 1970). A small adult produces fewer nymphs and also smaller nymphs than average (Murdie, 1969b; Dixon, 1970). When aphids are overcrowded or feed on host-plants of poor quality, many aphids reach maturity that might otherwise fail to mature because of the ability of the species to produce viable adults of a great variety of size, including very small adults (Way & Banks, 1967).

The genus Subhimalus is erected for the new species S. melanus on potato and S. fuscus on clover; Balclutha versicoloroides from clover is described as new.

Observations on the sexual behaviour, oviposition and responses to insect prey of the predatory Reduviid Vestula lineaticeps (Sign.) were made in the laboratory. Experiments with cardboard models indicated the importance of moving visual stimuli in eliciting predatory responses, but provided no evidence that olfactory stimuli play any such role. The responses of adult females towards other adults were apparently purely predatory. Males did not visibly discriminate between living females and other specimens (dead females, living or dead males) until they had seized them, when they displayed sexual responses with the living females and usually purely predatory behaviour with the remainder.

A total of 4418 mosquitoes caught by three collection methods at two levels in the forest near Belém, Brazil, were dissected to determine the proportion of parous individuals. About two-thirds of the mosquitoes belonged to Culex (Melanoconion) portesi Senevet & Abonnenc and C. (M.) taeniopus D. & K. The dissection technique entailed dissecting out the ovaries for examination of the tracheoles, whilst preserving the rest of the mosquito for later processing for virus recovery. Analysis of the results showed that, although significant differences were found in the parous rates from samples caught off human bait, and from mouse-baited Trinidad no. 17 and blower traps, these differences were unlikely to be of practical value when compared to differences in catching ability and ease of operation of the methods. In all, 2771 mosquitoes were classed as parous, and these when inoculated into baby mice in 142 pools yielded 14 isolations. It was concluded that the technique used did not reduce the likelihood of isolating viruses from the dissected mosquitoes.

During investigations into shoot-fly damage to guinea corn (Sorghum bicolor), millet (Pennisetum typhoides) and maize (Zea mays) in rain-grown plots at Samaru during 1966, it became obvious that attack was not attributable to a single species (Atherigona varia var. soccata Rondani (=A. indica infuscata van Emden)), as was previously believed. This species is undoubtedly the principal pest of guinea corn seedlings and young plants in northern Nigeria (Map 1), but there are also many other species involved. During the following four years field trials were undertaken to establish the relative importance of the species within the area and to learn something of their biology.