Sitona humeralis Steph. was successfully reared from egg to adult on potted lucerne plants. Soil pH was adjusted to 6·9, and soil additives were mixed with a ‘standard potting mix’ to produce a potting mix suitable for lucerne growth and S. humeralis development. Development was faster at 20 than at 15°C, but higher mortalities occurred at 20 than at 15°C.

Andaspis dasi Williams, which was described from India, is made a synonym of A. numerata Brimblecombe, which was described from Australia. The species is now known from several localities and host-plants in the Pacific area and is often found on tea. A short account is given of its association with the fungus Septobasidium in Papua New Guinea.

An investigation into the seasonal abundance of Zonocerus variegatus (L.) around Ibadan, Nigeria, showed that hatching occurs between October and March and peak abundance is in late November. Adults occur almost throughout the year. Oviposition takes place between March and October or possibly November, with a peak in April. Eggs laid in March and April hatch in October and November after a diapause, while those laid from June onwards do not appear to enter diapause. Thus eggs laid in June and July hatch at the same time as those laid in March and April. Parasitism by the sargophagid fly Blaesoxipha filipjevi (Rod.) during March and April results in a rapid decline in adult numbers which may be followed by a secondary peak in adult numbers when nymphs, which are present at the same time and are rarely parasitised, reach adult stage. Oviposition resulting from such a peak does not produce a secondary peak in hatching as this coincides with hatching from earlier layings. The fungus Entomophthora grylli plays an important role in controlling the abundance of nymphs and adults during the dry season despite the intermittent nature of the attacks. During the wet season, the fungus is able to germinate and disperse more readily, thus keeping the numbers of the insects low. It is concluded that there is one generation of Z. variegatus a year, with a peak in population coinciding with the dry season (November-March). It is suggested from the results that the grasshopper may have originated in the semi-arid zones of the north.

Large electrocuting nets were used at different seasons near a big tree in Zimbabwe to capture tsetse flies at different heights, distances from the bole and times of day. Some differences were found between species and sexes, but most flies were caught within 3·3 m of the ground and in the late afternoon. In the cool and wet seasons, Glossina pallidipes Aust. was less confined to lower levels than was G. morsitans morsitans Westw. Flies, especially fed males of G. pallidipes near the bole of the tree, were recorded in the greatest numbers in the midday period. Diurnal variations occurred in the relative proportions of females of the two species caught at different points. Releasing ox odour through an electrocuting net suspended at different heights confirmed that most flies were flying near the ground, especially in the hot dry season. Comparison of samples from the large electrocuting nets with those caught by other methods operated contemporaneously showed that the large nets gave samples which compared well with those from an electrocuting screen used in conjunction with a ventilated pit. Methods involving fly-capture by people gave very distorted results for all catch parameters examined. No method used gave consistently representative samples of replete flies or of newly emerged flies.

A translocation homozygous strain (TT) of Delia antiqua (Mg) was released into a field cage in Wageningen, The Netherlands, together with a standard laboratory strain (++). During the course of the season, the fecundity and fertility of the adults were measured together with the karyotype frequencies (TT+; T+; ++) of the F1 progeny. No selective disadvantage of the translocation karyotypes was observed. However, only four F1 adults emerged in the field cage; therefore a sample of pupae was removed from the cage, and it was shown that nearly 100% of the surviving pupae had entered diapause. This figure was confirmed from the remainder of the pupae. The fertility of eggs from the emerging adults was reduced to 54%, compared with the standard fertility of nearly 90%, but because of the diapause response of the strains used, the effect of this reduced fertility in the field-cage population could not be followed. The reasons for the change in diapause response of the laboratory strains are discussed and suggestions made as to how this could be prevented. The report highlights the importance of quality in control techniques involving translocations.

Observations on the taxonomy, distribution and host-plants of scale insects of several taxa in the Middle East are reported. A lectotype is designated for Bodenheimera rachelae (Bodenh.). Coccus capparidis (Green) is recorded for the first time from Israel and the Mediterranean region. C. arens Hodgson is a new synonym of C. capparidis. C. pseudo-magnoliarum (Kuw.) is recorded from Israel and France. The genus Paralecanopsis is regarded as a subjective synonym of Lecanopsis. Archaspis is synonymised with Quadraspidiotus and Archaspis ephedrae Bodenh. with Quadraspidiotus cecconii (Leonardi). The identity of Diaspis capparidis Bodenh. is established, the species is transferred to Rungaspis, and R. trabuti Balachowsky synonymised with it. R. macrolobis Kaussari is redescribed and a lectoype designated; it is recorded from Israel. A key is given to the three species of Rungaspis, and Sinaidiaspis is synonymised with this. Pseudococcus lindingeri Bodenh. is transferred to Planococcus, and Planococcus variabilis (Hall) synonymised with it. Trionymus internodii (Hall) is recorded for the first time from pineapple and from Israel.

Interspecies attraction studies in four species of bruchids (Callosobruchus analis (F.), C. chinensis (L.), C. maculatus (F.) and Zabrotes subfasciatus (Boh.)) showed that only males were attracted by the females of other species except in C. maculatus, the males of which were also attracted by males of Z. subfasciatus. C. chinensis showed no attraction towards any other species and none was attracted to it. On the other hand, C. maculatus males were attracted by females of C. analis and Z. subfasciatus and vice versa. C. analis and Z. subfasciatus showed no attraction towards each other.

Photoperiod was shown to be the principal factor regulating the induction of a facultative egg-diapause in Chortoicetes terminifera(Wlk.). All developmental stages from first-instar nymphs to immature adults were sensitive to photoperiod. At constant photophases, the insect exhibited a short-day—long-day response, with the upper and lower critical photo-periods for induction approximating to LD 15·5: 8·5 and 11:13, respectively. These correspond to the range of photoperiods experienced by the insect under natural conditions. The maximum inductive response occurred at about the mid-point of this range, i.e. LD 13·5: 10·5. In experiments in which insects experienced a change in photophase at the end of the nymphal stage, the incidence of diapause varied with the direction of change (long to short or short to long) and indicated that diapause induction was prevented by an increase in photophase but enhanced when the photophase was reduced. The size of the inductive response associated with a decrease in photophase appeared to depend less on the size of the decrease than on its position within the inductive range, such that the maximum effects were observed when the sequence of light regimes were close to or spanned the most inductive constant photophase. Temperature was also important in determining the induction of diapause. In the upper portion of the inductive range (15·5 to 12·5 h light), insects subjected to high temperatures or to an increase in temperature during development showed a lower incidence of diapause than those subjected to low temperatures or to a decrease in temperature. In the lower portion of the inductive range, the effects of temperature were reversed, with high temperature or an increase in temperature being more inductive than low temperature or a decrease in temperature.

The sexual competitiveness of males of Ceratitis capitata (Wied.) carrying a chromosomal translocation and a morphological mutation was compared to that of a wild-type strain. The competitiveness was evaluated by calculating from progeny data the proportion of females that mated with each male type. Males were introduced into the test population in varying proportions. The chromosomal translocation did not affect the competitiveness of the males. The presence of an eye-colour mutation (apricot) reduced the sexual competitiveness of the males bearing the translocation. The results showed evidence for a minority effect (an inverse relation between genotype frequency and mating success). The genetic background of the females in the test populations influenced the competitiveness of the participating males.

Four years of light-trap and crop survey data from the Namoi Valley of New South Wales are presented for Heliothis armigera (Hb.) and H. punctigera Wllgr. These suggest there are four generations a year. The associated seasonal sequence of major host-plants supporting successive generations, appeared to be: H. armigera—wheat; pre-flowering cotton; flowering cotton and sorghum; sorghum, flowering cotton and sunflowers; and H. punctigera—lucerne, linseed and medics; pre-flowering cotton; flowering cotton, sunflowers and soyabeans; lucerne, linseed and medics; pre-flowering cotton. On host-plants common to both species, a change in dominance from H. punctigera to H. armigera occured as each summer progressed. Suggested causes are: seasonal changes in the availability of host-plants, favouring H. armigera over H. punctigera; insecticide resistance in H. armigera; and the competitive superiority of H. armigera. Large numbers of H. armigera in cotton appeared to be related to: warm springs, which favoured moth emergence during the period of wheat anthesis; the incomplete control of infestations within cotton itself, leading to the development of resident populations; and the influx of moths from other host-plants, especially sorghum, during the latter half of the season.

A pyralid moth belonging to the tribe Anerastiini, reared from larvae feeding in the rhizomes of Johnson grass (Sorghum halepense) in Pakistan, is described from the male and female and named Patna rhizolineata sp. n. It is differentiated from the closely related Afrotropical species P. venatella Hmps. As a result of the comparative study of type material, P. brunneicostella Hmps., Critonia sarcoida Hmps. and P. aulacodes Meyr. were found to be conspecific with P. venatella and are placed as junior synonyms of it.

The population dynamics of the leafhopper Neoaliturus fenestratus (H.-S.) was studied at two temperatures (20 and 25°C) and on a summer host-plant (safflower) and a winter host-plant (Chrysanthemum segetum).

The life-span, reproduction and computed rates of increase were established, and it was found that the leafhopper performed best on safflower at 25°C. Delayed mating induced longer survival in both sexes. C. segetum, the winter host-plant, enabled long maintenance of the insect, although markedly reducing its rate of reproduction. The implication of these findings for the seasonal cycle of the leafhopper is discussed.

Egg-batches of Spodoptera littoralis (Boisd.) collected in Crete showed an abnormal sex ratio; 24% yielded predominantly female adults. The field data and data from nine generations of a laboratory strain, which also produced predominantly female offspring, showed that this abnormal condition was transmitted between generations by the females. The mean percentage hatch of egg-batches collected from the field which produced females only was 59·6, and the mean percentage hatch of the eggs of the laboratory strain was 58·8. These results suggest that the production of females only is a result of the mortality of the male embryos. Occasionally, abnormal females from the laboratory strain reverted to producing offspring of both sexes. This recovery from the abnormal condition became more common as successive generations were bred in the laboratory. One female of a normal strain produced all-female offspring and descendants of this female were similarly affected. The females of the unisexual laboratory strain were similar in appearance to normal females but laid significantly smaller egg-batches.

The natural predators of larvae and pupae of the complex of Simulium damnosum Theo., most probably S. soubrense Vajime & Dunbar and S. sanctipauli Vajime & Dunbar, in the River Marahousé in the Ivory Coast were identified by serological methods. Rabbits were injected with cell-free saline extracts of S. damnosum larvae to produce S. damnosum antiserum, which was used in interfacial capillary ring tests. A total of 1648 gut smears was made from various aquatic invertebrates and tested, and Trichoptera larvae were identified as the most important predators.

Attention has recently been focussed on the problem of why mosquitoes feed on some people more than others. In this paper, investigations of selective feeding by mosquitoes of the Anopheles gambiae Giles complex conducted in two villages in the Gambia are reported. Fed mosquitoes were collected from the bed nets of 35 groups of people who normally sleep together, for example mothers and infants or two children or two adults. A total of 2339 meals was analysed using haptoglobin or ABO typing to determine from which individual each meal had been obtained. The results showed that the proportion of feeds upon an individual in a group can be associated with the proportion of the total surface area or weight of the group contributed by that individual. The incidence of multiple feeding was between 3 and 6%. The results are discussed in relation to host selection by mosquitoes and their significance for models of malaria epidemiology.

A gall midge that attacks citrus flower buds in south-western Japan is redescribed under the name Contarinia okadai (Miyoshi) comb. n. and is compared with C. citri Barnes, which was originally described from cultivated citrus in Mauritius. C. okadai, for which a neotype is designated, is distinguished from C. citri by morphological characters of the adult males and females and of the larvae. The known host-plants, biology and distribution of C. okadai are recorded, and new Japanese and English names for the species are proposed. The status of records of C. citri from Sicily, Cyprus, Israel, India, China and Hong Kong is discussed, and the need for further taxonomic research is stressed.

Amongst 20 tea clones tested in Sri Lanka for susceptibility to Glyptotermes dilatatus (Bugnion & Popoff), five of the high-yielding soft-wooded clones, including the currently recommended and popular TRI 2023 and TRI 2026, were found very susceptible and to suffer a severe net loss in yield. A highly significant negative linear correlation was observed between the mean infestation percentage of clone with an infestation of over 30% and the mean percentage change in yield. In general, the high-yielding clones with soft-wooded sappy frames were particularly susceptible to termite attack. Since yield is one of the important criteria for selection, it is suggested that in areas prone to termite infestation, replanting should be limited to the high-yielding resistant clones such as GMT 9, KEN 16/3 and DG 39. The provision of shade with Gliricidia sepium may have prevented a steep increase in the incidence of infestation in the susceptible clones.

The population dynamics of Pineus pini (Gmel.) was examined in two locations in the Kenya Highlands where the mean annual precipitation ranges from 620 to 1400 mm. Variations in population densities were related to rainfall. Generally, there was a marked decrease in population during the three months of heavy rainfall in March to May and a significant increase during dry weather from August to October. This was followed by a slight decrease in the rate of population build-up, until the long rains in April again resulted in another population collapse. Nine species of predatory insects were identified, and population fluctuations of the most common of these, Exochomus spp., was studied. Predators seemed to remove about 12% of the aphid population. Other mortality factors included heat and crawler dispersion. The greatest mortality occurred early in the life-cycle and was mainly due to eggs and crawlers being washed off the host-tree by rain.

Orius amnesius sp. n., a predator of Megalurothrips sjostedti (Tryb.) infesting cowpea, is described from the male and female from Nigeria. A sympatric species, Orius albidipennis (Reut.) was also attacking the pest. Wollastoniella gatti sp. n., a predator of tetranychid mites on ornamental species of Solanum, is also described from the male and immature examples from Kenya. O. amnesius resembles O. albidipennis and several other economically important and widely distributed species of Orius found in Africa, Asia and the Pacific.

A relationship between mean development rate, temperature and saturation deficit was derived for the egg stage of Lucilia cuprina (Wied.). Development rate increased linearly with temperature between 10 and 40°C at constant saturation deficits. Increasing saturation deficits between 0 and 10 mm Hg caused non-linear decreases in development rate. At zero saturation deficit, temperatures between 15 and 40°C had no effect on egg survival. Survival in the egg stage declined rapidly with increasing saturation deficits, primarily through the inability of the larvae to rupture the chorion of the egg. The aggregation of single eggs into compact egg-masses during oviposition appeared to afford no additional protection against desiccation. The ecological implications of the results are discussed.