Descriptions are given of five new species of Azotus Howard from the Ethiopian region, including one from Mauritius. These bring the total number of Azotus species known from this region to eight. Two described species, A. capensis Howard and A. elegantulus Silvestri, are annotated and figured, and a key to the species is given. The related genus, Ablerus Howard, is recorded from Africa for the first time on the basis of a new species from the eastern Cape Province, and a new East African species of Physcus Howard, is described. A second East African species of the latter genus, one with flightless females, is characterised but not named to species.

The attractiveness, to mosquitoes, of human subjects breathing normally and wearing a breathing apparatus which removed 95·5% of expired carbon dioxide were compared in the field. Significantly fewer mosquitoes approached the subject with a reduced carbon-dioxide output. Species differences were apparent in the degree of reduction of mosquitoes at the bait, as measured by the ratio of numbers attracted to subjects without and with the breathing apparatus. From the results of trials in the Gambia, West Africa, this ratio gave values of 0·67 for Mansonioides spp., 0·46 for Anopheles gambiae Giles/A. melas Theo. and 0·19 for Culex thalassius Theo., while complementary work in southern England gave a value of 0·34 for Aedes cantans (Mg.)/Ae. annulipes (Mg.). A reduced carbon-dioxide output had no effect on the proportion of mosquitoes attempting to feed once within close range of the host. These findings confirm that carbon dioxide is a long- or medium-range attractant.

A series of laboratory experiments was made on the citrus bud mite Aceria sheldoni(Ewing). The postembryonic stages consist of larva, nymphochrysalis, nymph and imagochrysalis, each of which lasts 1–2 days, and imago, which lasts about two weeks. The nymphochrysalis and imagochrysalis are inactive pre-ecdysial stages, while the others are true active stages. The mite shows facultative arrhenotoky. Adult males deposit stalked spermatophores from which the sperm masses are taken up by virgin females. At 24–0°C fertilised females laid eggs that produced offspring consisting of 7–25% males. The males deposited 25–100 spermatophores (2–15 daily) during their adult life, with occasional interruptions. Spermatophores exposed for one hour to relatively extreme temperatures of < 5°C or > 38°C did not fertilise eggs. Mite populations from lemon trees usually comprised a low percentage of males in winter and a high percentage in spring and autumn.

In both experimental and naturally developed colonies, Aphis fabae Scop., and Acyrthosiphon pisum (Harris) were concentrated on the upper parts of broad bean plants. A. pisum resembled Myzus persicae (Sulz.) rather than Aphis fabae by normally infesting leaves, not stems. Colonies of M. persicae were dispersed over the whole plant. In laboratory experiments, apterous adult aphids were observed walking on bean plants, and their activity was recorded in terms of their actions at each node. Moving aphids of both species tended to maintain their direction at a node although the structure of the plant does not appear to favour this. Aphids of both species changed their direction of movement more often after going onto the leaf at a node than when they stayed on the stem. M. persicae adults went upwards as often as they went down, but those of Acyrthosiphon pisum walked up more often than down and were more likely to turn round if they were moving downwards. These differences in the behaviour of active individuals would tend to produce the differences between the observed spatial distributions of the two species, although other factors, including leaf age and reproductive rates are probably more important in determining the form of aphid colonies.

The species-patterns and incidence level of ticks on the larger wild animals and on rodents were examined between 1966 and 1969 in the Southern Province, Zambia. The rodents, except for the elephant shrew, porcupine, and hare, were infrequently infested. The antelopes, except for the eland, had a mean infestation of under nine per individual, the buffalo, zebra, suids and the eland over 20. Twenty species of ticks were found on these hosts. On the ruminants Hyalomma rufipes Koch was absent, and H. truncatum Koch was the most frequent; Rhipicephalus simus Koch, R. tricuspis Dön. and R. pravus group were common. Boophilus decoloratus (Koch) was rare, R. evertsi Neum. infrequent except on zebra and lechwe, and R. appendiculatus Neum occurred on only four of the 15 ruminant species examined. Except on the elephant, Amblyomma was represented solely by A. pomposum Dön.

Periodic deticking of cattle, sheep and goats yielded precise quantitative information on the seasonal changes in incidence and species-patterns of ticks. Eighteen species were found on the domestic herbivores. On cattle B. decoloratus was usually numerous and often dominant, except where controlled by dipping or spraying. Compared with infestations on wild animals, H. rufipes was frequent, A. pomposum was replaced by A. variegatum (F.), and R. evertsi and R. appendiculatus were numerous; R. simus, R. tricuspis and the R. pravus group were usually in relatively low numbers.

The proportions of the different species on cattle varied widely between the stations and at different seasons. Intensive stocking, with resultant grazing down of the fieldlayer, increased the R. evertsi numbers markedly throughout the year, and depressed the numbers of Hyalomma sp., A. variegatum and of the less common Rhipicephalids during the dry season; except for A. variegatum, their numbers and those of R. appendiculatus rose, however, during the wet season to higher levels than on the less intensively stocked paddocks. Some evidence is presented that Barotse cattle are more heavily infested than Sindhi and Boran cattle.

One field and four laboratory trials were run to determine the reason for the success of 1–8% malathion in diesel oil in controlling Culicoides furens (Poey) in swamp mud in Jamaica. In the laboratory malathion and marine diesel oil (1:4000) was an effective larvicide for up to two days after application to the mud, but diesel oil alone gave only slight mortality even after six days. Judged by the emergence of adults, diesel oil gave 100% pupal mortality for five days and still showed some effect after four weeks; this effect was not improved by the addition of malathion. In the field, counts of emerging adults showed that diesel oil at 106–5 gal/acre gave 97–8% control of C. furens for up to eight weeks after application. It is concluded that, because of the possibility of pupicidal action, insecticides should be assessed on adult emergence rather than larval mortality.

Male bushflies (Musca vetustissima Wlk.) are attracted to and feed on proteincontaining substances, although under laboratory conditions they ingested smaller quantities of blood and dung than did the females. Laboratory experiments showed that they are able to obtain water from fresh dung and blood, but no physiological requirement for the protein was found. Feeding on protein did not increase the life span or the total numbers of matings; it did not improve the mating success of males that had previously been multiple-mated; and it did not enhance sexual activity, contrary to the situation found in Lucilia cuprina (Wied.). It is concluded that protein feeding in male bushflies is casual, possibly a behaviour pattern that ensures their presence near females.

An attempt to control Graeffia crouanii (Le Guillou) with systemic insecticides injected into the trunk of coconut palms indicated a high potential for monocrotophos and dicrotophos. The fronds of 15-year-old palms treated with 6–7·5 ml active ingredient per palm were toxic to adult females for up to 16 weeks, and make a second treatment unnecessary. An analysis of coconuts from palms treated with monocrotophos (6 ml a.i.) showed no significant residues in the nut water or meat.

The taxonomic status of Caryedon pallidus (Olivier) is discussed and its identity related to a species found in West Africa breeding in seeds of Cassia obtusifolia. Specimens of Caryedon breeding in Cassia senna from the Nile basin are shown to be a distinct species. This, and a further species from Armenia, both of which had been previously misidentified as Caryedon pallidus, are described as new.

Adults of the cabbage root fly (Erioischia brassicae (Bch.)) fed on 0·1% tepa in 10% sucrose solution during the second and third days after emergence laid over 95% sterile eggs. Nearly complete sterility was also obtained from females fed on 0·l% tepa for two days between mating and oviposition. Tepa at 0·1% did not affect longevity of either sex or the competitiveness of treated males, although at higher concentrations longevity was reduced. When flies were enclosed in a large field cage and provided with food baits containing 0·1% tepa, sucrose and leucine along a hedgerow, 70% of the eggs laid were sterile.

The effects of residual sprays of methoxy-DDT wettable powder at 2 g/m2 on the mortality and behaviour of Anopheles gambiae Giles, Mansonia uniformis (Theo.) and Culex pipiens fatigans Wied. females were investigated in four verandah-trap huts, one of which was used as control. The overall mortality of no species ever exceeded 29%, and no consistent deterrent effect on entry was demonstrated. The proportions of mosquitoes in the exit traps were, for A. gambiae 80–90% in treated huts and 29–70% in the control, for M. uniformis 90–100% in treated and control huts, and for C. p. fatigans 26–84% in treated huts and 38–66% in the control. There were more unfed mosquitoes of all three species in the treated huts than in the control, for A. gambiae 35–64% and 10–53%, respectively, for M. uniformis 38–84% and 35–64%, respectively, and for C. p. fatigans 22–58% and 21–43%, respectively. Bioassays with wild-caught A. gambiae exposed to the treated surfaces for one hour, showed that the deposits remained highly toxic for 16 weeks on grass, six weeks on iron and two weeks, or less, on mud.

The effect of water currents on the dispersion of the larvae of Aedes aegypti (L.) and Anopheles stephensi List, were examined in the laboratory. The larvae represent two distinct respiratory positions, and on the basis of their amount of movement were termed active and inactive, respectively. While active larvae resist water currents, and tend to disperse evenly in a field system, inactive larvae tend to be washed away but also to accumulate in loci of minimal water movement. These findings could be applied to detection of larval populations, control by irrigation and spot chemical treatments in rice fields.

Aulacaspis tegalensis (Zhnt.) (Diaspididae) infests the stems, and to a lesser extent the leaves, of sugar-cane. It is indigenous to Malaya and the islands of S.E. Asia, and has been introduced to the Mascarene Islands and East Africa. Its biology and economic importance were studied in Mauritius. Development and construction of the scale in both sexes are described. The life cycle takes 3–9 weeks, the female laying 700–800 eggs over 10 weeks in summer and 14 in winter. Feeding in the stem is in the parenchyma; the path of the stylet is intracellular and vascular bundles are avoided. Stem surfaces are essential for population increase. The leaf sheaths which invest stems tightly or loosely according to their age, have a decisive role among factors that influence intensity and pattern of stem infestation. Field infestations may be severe in dry coastal areas. Populations increase in March-May, and decline in July-November. The determining factors are seasonal weather, crop growth, harvesting and natural enemies. Dispersal, by the eggs and crawlers, is passive. Adelencyrtus miyarai Tachikawa (Encyrtidae) is constantly associated with Aulacaspis tegalensis and is heavily hyperparasitised by Tetrastichus sp. (Eulophidae). The most frequent predators are Lindorus lophanthae (Blaisd.) (Coccinellidae), Cybocephalus mollis Endrödy-Younga (Nitidulidae) and mites. Predators are important only in the regulation of large A. tegalensis populations. Reductions in the sucrose content of the cane juice are directly proportional to the numbers of scales present on each interaode; growth of canes is not obviously affected, but grown canes may die before harvest. Reduced germination and growth may result from use of infested propagative material. Practicable control measures comprise use of clean or hot-water-treated propagative material, field hygiene and block harvesting, removal of dry leaves to expose the stems, and varying the date of harvest.

The distribution, habitat and cultivated and wild host-plants of the four species of Oxycarenus found in Ghana are given. O. hyalinipennis (Costa), primarily a savanna species, attacks the seeds of okra, kenaf and cotton; the other species are unlikely to attain pest status. A key to the species is given.

A distinct black species of Cicadulina from sugar-cane in East Africa is described as new, and notes on the distribution of other Cicadulina spp. are given.

A year-long survey of the breeding of Glossina morsitans Westw. in the Moremi Game Reserve, northern Botswana, was based on transect counts of pupae and empty puparial cases under logs. Levels of breeding were lowest during the hot dry months, and were similar in riverine woodland and mopane even when the latter was leafless: mopane contributed most pupae (65.7%) to the total population because of its greater area. Pupae to cases ratios decreased between February and November due to accumulation of cases, which apparently were largely destroyed in the rains. Comparison of holes, scattered sites and logs in a second survey showed that holes were important breeding sites during the hot dry season, possibly due to their higher humidity, but that at other times most breeding occurred in scattered sites. During the rains scattered sites contained the fewest dead pupae, and holes the most. There was a preference by G. morsitans for shaded sites. Breeding appeared to be depressed during the rains, possibly due to reduced availability of food hosts, particularly warthog.

Hispaniella africana sp. n. is described from material reared from Inchoaspis dentilobis (Newst.) (Horn., Diaspididae) attacking Sapium ellipticum (Euphorbiaceae) in Uganda. This is the first record of the genus from tropical Africa.

Ketumala thea sp. n. is described from tea and the shade trees Erythrina lithosperma and Glirididia sepium in South India. Descriptions are also given of K. singapurana sp. n. and K. nigropunctata (Distant) comb. n.

In experiments covering many successive generations of Musca domestica L. (strains NS and WHO/SRS/MHSCO domestica/1), sublethal doses of p,p'DDT applied topically to adults or fed to larvae or adults had no effect on the numbers of abnormal follicles, but the numbers of normal follicles increased in F1–3 when larvae were fed with diet containing 10 parts per million of DDT. These results conflict with those of previous workers. Other possible causes of abnormal oogenesis were examined. Sublethal doses of o,p'DDT and DDE (an impurity and metabolite, respectively of p,p'DDT) had no effect, whereas inbreeding and high-density rearing caused the numbers of normal follicles to fall; the latter caused the numbers of abnormal follicles to increase. There were also heritable differences in oogenesis among three strains of house-fly.

Sperm-transfer in Culicoides melleus (Coq.) is achieved by means of an intermediary spermatophore. The form of the spermatophore, only the second to be observed in a species of Culicoides, is described and illustrated. Though generally similar to others reported in Diptera, the spermatophore of C. melleus is distinguished by the presence of a long neck attached to the main capsule. Formation of the spermatophore occurs after sexual union has been achieved, and throughout mating the capsule remains held in the male apparatus. The distinguishing functional feature is that the entire length of the neck lies within the common duct of the spermathecae. The presence of an appendage of the spermatophore inside the spermathecal duct is a hitherto unknown phenomenon in Nematocera.