When the compound eye of the adult of the planthopper, Myndus crudus, is light-adapted, pigments are condensed in a zone proximal to the crystalline cones. Viewed externally, the eye is straw-colored. When dark-adapted, pigments migrate distally into the region of the crystalline cones and thus are closer to the cuticle. Viewed externally, the dark-adapted eye is maroon-colored. The eyes of most adult M. crudus observed during daylight hours were light-adapted. Eyes of males and females changed from the light to the dark-adapted condition between sunset and ½hr after sunset. When planthoppers with light-adapted eyes were placed abruptly into darkness at a temperature of 25–27°C, the eyes became dark-adapted within 15–30 min. When planthoppers with dark-adapted eyes were placed abruptly into light, the eyes became light-adapted within 30–60 min. At 8°C the planthoppers were immobile, and light-adapted eyes had not changed to the dark-adapted condition within 45 min. Eyes of M. crudus nymphs, which live in the root zones of grasses, are dark red and do not change color in response to changes in light. Field samples showed that adult M. crudus were active in coconut palms during the day and night, but higher numbers were caught during the day (P < 0.01).

Studies on aspects of the biology of the kola weevil Balanogastris kolae on Cola acuminata and C. verticillata were made in the laboratory at temperatures of 28–30°C. Mated females of B. kolae oviposited a significantly higher number of eggs (238) in C. acuminata than in C. verticillata (205) when confined separately with the nuts. But when the weevil was offered the choice of three Cola species as oviposition media, significantly more eggs were oviposited in both C. nitida and C. verticillata than in C. acuminata. However, there was no significant difference between the number of eggs oviposited in C. verticillata and C. nitida.

The average total incubation, larval and pupal developmental periods of B. kolae in both C. nitida and C. verticillata were 6, 16.2 and 6.1 days, respectively. The average total developmental period in C. acuminata was 28.8 days, and 26.5 days in C. verticillata. Although the total developmental periods overlap, there was a significant difference between the periods of development of B. kolae in the two Cola species. Oviposition and development of B. kolae in the wild species, C. verticillata, coupled with its wide distribution show that it may be ecologically important in the survival of the weevils, especially when the cultivated Cola species are not available in the field.

Part of the female reproductive system of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) consists of two spermathecal glands each with a duct and receptacle. The receptacle is composed of secretory cells with the normal secretory apparatus (secretory vesicles, rough endoplasmic reticulum, mitochondria and microvilli), as well as bundles of microtubules. The extensive rough endoplasmic reticulum is indicative of the production of proteinaceous substances. On the basis of histochemical tests, the material in the epithelium and lumen of the spermathecal receptacle appears to be a mixture of carbohydrate and protein. These materials accumulate in cavities within the epithelial secretory cells, and are then transferred to the main lumen of the receptacle in which sperm are also stored.

The oviposition site preference of the legume pod-borer on cowpea plants was studied under screenhouse conditions using an egg marker technique. Flowers, flower buds and abscission scars were found to be the most preferred sites. The results obtained in the screenhouse tests were in general agreement with those obtained under field conditions where presence of young larvae (first and second instars) was used as the indicator of oviposition sites.

The sorghum shootfly, Atherigona seccata Rondani, is the main species of Atherigona attacking cultivated and wild species of Sorghum in Africa and Asia. The past 55 years' research on the pest has produced means for its management. The bionomics of A. soccata are well known and are being applied for its cultural control by adjusting planting dates. Natural enemies of the shootfly are few and their biology little known. The systemic insecticide carbofuran as a seed and seed furrow treatment provides effective fly control where the cost-benefit is favorable. Sources of host plant resistance to shootfly have been recognized for about 35 years. Incorporation of this resistance in high yielding varieties through plant breeding should be more rapid now that the mechanisms of resistance and their inheritance, through additive gene action, are better understood. These resistance factors include non-preference for oviposition, antibiosis and recovery through tillering.

The morphology and function of the trifoliate organ of five species are studied. Two examples are given where the ultrastructure of this organ assists the interpretation of speciation. The movement of the trifoliate organ during the courtship of Atherigona laevigata and its position during copulation is briefly described. A simple (A. seccata) and a complex (A. conigera) organ are described in detail, with emphasis on structure and function of the sensilla, and surface microsculpture. The A. hancocki-group organs are described and possible functions are suggested for these unusual structures. A distinct population is separated from the A. lineata species complex. A group of three species A. steeleae, A. secrecauda and A. matilei are confirmed to have a close, natural relationship.

The sternal gland shows significant differences in size and activity in different instars of the worker caste of Trinervitermes bettonianus. Gland size (volume and surface area) was not significantly different between instars 1 and 2, and 2 and 3; but was significantly different between these age groups and instars 4–7. The potential trail-laying activity of the gland of a worker increased from zero to 50 trail units in the course of development from the first to seventh instar. The relatively high biological activity of the gland in the older instars 5–7 may be of ecological significance, since these stages were found to constitute over 90% of foragers under field conditions.

The pupal parasitoid Xanthopimpla stemmator Thunberg oviposits in the pupae of the spotted stalk borer (or sorghum stem borer) Chilo partellus (Swin). The adult parasitoid emerges from the pupal case, killing it in the process. Ten mated females of the parasitoid had an average longevity of 30 days (maximum 37 days and minimum 22 days). The number of progeny produced ranged from 71 to 115, with an average of 84.5. The male:female sex-ratio of their progeny averaged 1.14:1. The maximum mean progeny production per day (mx) was 1.9. The innate capacity for increase was 0.131 per female per day; and the population multiplied 43.43 times in the generation time of 28.78 days.

Wild-caught phlebotomine sandflies were captured from rock crevices and termite hills and released into feeding cages containing various species of laboratory animals, to find suitable hosts for feeding flies for experimental or breeding purposes. Flies captured from rock crevices did not feed as well as those human-baited at termite hills. The ubiquitous species from the termite hills was Phlebotomus martini, the major vector of kala-azar in the study area (Machakos District of Kenya). This anthropophilic species feeds readily on the mammalian laboratory animals. Cooling flies before feeding stimulated them to feed.

Purified suspensions of macerated cuticular lesions from the insectary-reared tsetse Glossina morsitans morsitans were applied on laboratory-reared newly emerged teneral tsetse by three pathways: topical application on the ventral abdominal integument, oral microfeeding, or microinjection into the haemocoel. A second group of flies were subjected to teratological wounding pin-stabs, forcep-pinch and shallow blade-slits, all in attempt to induce cuticular lesions. Samples of tsetse were examined every week for 11 weeks. Application of cuticular lesion suspensions did not result in lesion formation, but three types of lesions were formed due to physical damage induced artificially on the integument.

Total haemocyte counts (THCs) and differential haemocyte counts (DHCs) were also determined for tsetse with, and without, lesions. THCs were significantly higher (P < 0.01) in tsetse with cuticular lesions than in those without lesions. DHCs showed a high number of large spindle-shaped cells and thrombocytoids in the flies with lesions (P < 0.05).

Trichoid, basiconic and campaniform sensilla have been observed on the ovipositor and tarsi of the sorghum shootfly, Atherigona seccata Rondani. The ovipositor of A. seccata comprises abdominal segments 6–9, with most of the trichoid sensilla located on the ninth segment. Two olfactory pegs each are located on the paired leaflets of the ninth segment. Sensilla on the tarsi include long and short basiconic sensilla and campaniform sensilla located near the anterior margin of the last tarsal segment.

The sensory organs on the head capsule of the larva were studied by light, scanning and transmission electron microscopes. Four types of sensory receptors were observed on the cephalic lobes. They consist of four knob-shaped sensilla, two styloconic sensilla, two campaniform sensilla, and eight basiconic sensilla.

The results of this experiment, where insect defoliation was simulated by artificial defoliation, suggest that Pinus kesiya and P. oocarpa trees in Zambia survive after complete defoliation, and that the reduction in growth may remain economically tolerable.

Teneral nulliparous tsetse Glossina pallidipes were infected with virus-like particles by two pathways: haemocoelic microinjection, and oral feeding with a micropipette. Samples of tsetse were dissected every 3 days; and at 22 days post-infection, cumulative per cent infection was 44.4 and 31.3% for microinjection and per os infection, respectively. Natural virus-like particle infection in the population was 3.6%. Thus the infectious nature of virus-like particles was established, together with two possible pathways of infection.

This paper describes the results of extensive rearing of shootfly species of the genera Atherigona and Acritochaeta from cultivated and wild Gramineae in Andhra Pradesh, India. Nineteen fly species were recorded from 41 graminaceous species including cultivated sorghum. Atherigona soccata, an important pest of sorghums in the Old World tropics, was reared from 22 host plants. Only cultivated and wild species of sorghum were important as hosts of this pest species. It was observed that alternative host Gramineae were of minor importance in the ‘carryover’ of Atherigona soccata through the off season, but the irrigated sorghum grown for fodder could be an important source of flies.

In general, shootflies of a particular species usually favored one graminaceous host above others. The numerically dominant fly reared from wild Gramineae was Atherigona falcata, which was recorded on 17 hosts, including sorghum. Other common species in Gramineae were Atherigona pulla, Atherigona oryzae, Atherigona punctata and Atherigona atripalpis, all of which were also reared in very low numbers from sorghum. Five new species of Atherigona were reared; three of these will be described shortly.

During three seasons of observations similar populations of the jassid Empoasca lybica were recorded on two different eggplant cultivars (cvs). However cv Black Beauty exhibited more tolerance to jassid attack than cv Long Purple. Comparing jassid-infested and jassid-free treatments, the growth and yield of Long Purple plants were reduced more drastically by the insect than were those of Black Beauty.

As an important measure for increasing grain production, hybrid sorghum has been cultivated in the whole area of the Peoples Republic of China since 1970. Over the past 10 years the sorghum shootfly has gradually become the worst pest of sorghum in several places in the southern parts of China. In 1973, some regions of Gung Dong, Gui Chou and Gung Xi Provinces were affected by the shootfly with a rate of 30% for the heavier damage, and a few even exceeding 90%.

In a bluetongue (BT) disease project, light trappings of Culicoides were conducted in 19 localities and 39,000 biting midges were examined. BT virus type 16 was isolated in 1968 at Devora from a pool consisting mainly of Culicoides schultzei gp and C. imicola; BT virus type 4 was isolated in 1969 at Yesodot from a pool of 183 C. imicola; BT virus type 2 was isolated in 1979 at Talmé El'azar from pools consisting of 2462 C. imicola; and BT virus type 6 was isolated 3 times in 1980 at Bet Dagan from pools of 204, 258 and from 143 C. imicola, respectively. In the Akabane project (1976 and 1977) 4632 Culicoides and 1867 mosquitoes from four localities were trapped and examined. An arbovirus which was not Akabane, BT or turkey meningo-encephalitis (TME) was isolated from a pool of 44 engorged Culex pipiens complex trapped in Gan Shemuel. In the Rift Valley fever project, which was conducted in 1978 and 1979 due to the presence of an epidemic in Egypt, 351 mosquitoes of four species and 7098 Culicoides of 14 species were tested and none were found to harbour an arbovirus. Within the TME project more than 12,000 Culicoides and 9000 mosquitoes from 14 localities were tested. Positive isolations of TME were made from an unsorted pool of mosquitoes from Gesher haziw, an unsorted pool of 13 Culicoides from Nahalal, a pool of 223 unidentified Culicoides from Zetan and a pool of 12 engorged Cx pipiens complex from the same locality. Other pathogens which were not identified to species level were also isolated.

Following the 1978 epidemic of yellow fever in The Gambia, the distribution of the potential vector, Aedes (Diceromyia) furcifer/taylori group, was studied during the 1979 rainy season. Evening biting catches conducted in villages throughout the country revealed that A. furcifer/taylori was the most abundant vector biting man in the east of the country where the 1979 epidemic had its focus. Taxonomic studies showed that only A. furcifer and not A. taylori was present.

A total of 1584 young sorghum plants showing typical ‘dead-heart’ symptoms were collected from the field at weekly intervals in 1978 and 1979. From these emerged adult flies belonging to eight families and 17 genera. Members of six of the families are scavengers, while those of the remaining two, Muscidae and Chloropidae, are phytophagous, causing primary or secondary damage to the plants. Three hundred and seventy-five Atherigona soccata adults emerged, representing only 23.7% of the damaged plants. This contrasts with previous records that rate Atherigona soccata as the most important source of ‘dead-heart’ damage in young sorghum plants. Other shootflies perhaps of similar importance, also reared from the plants included Oscinella spp. (986), Scoliophthalmus spp. (344) and Anatrichus erinaceus (160). There were a few other less abundant species.

The numbers of probable parasites and predators of the shootflies that emerged were insignificant, when compared with the extent of damage and the numbers of the shootflies. Damage caused by the shootflies to the early plantings was low and insignificant, reached a peak in mid-season and remained high until the cessation of rain at the end of the season.