Puparia of Glossina austeni Newst. and G. morsitans Westw. contain similar quantities of chloroform-soluble substances (referred to as fat) in relation to their nonfatty dry weight at the beginning of puparial life. However, adult G. austeni emerge from their puparia with significantly larger fat reserves than G. morsitans after development at 25°C. This obvious difference in the rate of fat consumption by puparia of the two species is not accompanied by differences in the rate of oxygen consumption, neither do respiratory quotients explain the difference. It is therefore concluded that some substrate other than fat may be used as a supplementary energy source in G. austeni, since there appears to be no species difference in the composition of fat. Thus the calculation of an oxygen equivalence of fat for tsetse flies is invalid for different species and may also vary within a species depending upon the temperature at which development proceeds.

Transmission of cabbage black ringspot virus to turnip plants by Myzus persicae (Sulz.) was reduced by foliar sprays of five parts per million gibberellic acid together with 0·2% ammonium nitrate, but not by each applied separately. The reduction occurred at 10°C but not 15, 20 or 25°C, and at a light intensity of 10 000 lux but not at 5 000 lux. The response was usually only evident towards the end of the normal range of the incubation periods, indicating that protection was probably only achieved when relatively small amounts of inoculum were introduced. The reduced transmission could not be related to aphid behaviour but changes were found in the free proline content and fine surface structure of treated leaves, and it is suggested that the results are to be interpreted in terms of changes in host cell metabolism.

The effects of sublethal doses of insecticides and unrelated environmental stresses on Dysdercus fasciatus Sign, were studied in the laboratory. Dieldrin applied topically to fifth-instar nymphs at 02–0·6 μg/individual increased egg production, at 0·8–60 μg/individual decreased egg production, and at 0·6–60 μg/individual decreased fertility. Applied to adults, dieldrin at 2–4 μg/individual reduced egg production, and at 0·02–0 08 μg/individual (males) and 0·2–0·8 μg/individual (females) shortened the life span. In a separate experiment, dieldrin at 0·2 μg/individual reduced egg production when applied to fourth-instar nymphs, but had no effect on fifth-instar nymphs or adults. p.p'DDT at 6 μg/individual applied topically to unmated females increased egg production. Exposure of all life stages to 0·06 mg DDT/ litre for two generations was followed by increased egg production and fertility: shorter exposure at 1 mg DDT/litre had no effect, and at 6–20 mg/litre egg production and fertility were reduced. Rearing on boiled cotton seed resulted in small adults with low gg production and fertility, the eggs being longer than normal. Crowding nymphs (24 individuals/200-ml cage) had the same effect on the size of the resultant adults. Starvation caused low egg production and fertility. Fluttering of males during a free fall (a measure of activity) was increased by crowding (maximum at 2 individuals/cage), by topically applied dieldrin at 0·04–0·08 μg/individual and DDT at 3–5 μg/individual, by two-generation exposure to 0·06 mg DDT/litre, but not by feeding on boiled cotton seed.

A simple X-ray method for detecting sorghum midge (Contarinia sorghicola (Coq.)) larvae and pupae in infested spikelets of grain sorghum (Sorghum vulgare) is described and illustrated. Undamaged ovaries were easily and accurately detected in the radiographs, but the detection of spikelets that had been attacked by midge was less accurate. Diapause larvae showed up clearly in the radiographs but pupae often produced indistinct images, possibly because they were dead. X-ray examination therefore tended to underestimate midge infestation. It is concluded that this radiographic technique is less accurate than dissection, but might be used for rapid general field surveys and for in vivo observations of larval development within infested spikelets.

Studies on the egg diapause of Teleogryllus commodus (Wlk.) in southern Victoria, and the effect of latitude on the intensity of diapause in Teleogryllids have led to the concept of population suppression by the genetic elimination of diapause. The method is based on the finding that males of the closely related T. oceanicus (Le Guillou) transmit the non-diapausing trait when crossed with T. commodus females. An additional suppressive factor is imposed by sterility in the progeny of the cross. An evaluation of the feasibility of this approach has been carried out in small-scale trials using field enclosures in which known populations of both types were studied. With a 10:1 ratio of non-diapausing/diapausing males, a mean of 73–8% of the eggs from the T. commodus females were hybrid, and with a 5:1 ratio 50–8%. The practical application of the method will not be attempted until the relative suitability of a number of candidate non-diapause biotypes has been determined.

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.

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.

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.

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.

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.

A laboratory colony of Glossina morsitans orientalis Vanderplank had been kept successfully in Edinburgh for 18 months, when reproduction ceased because of a high incidence of abortion and follicular degeneration. A comparison of these flies with imported Bristol-bred flies showed that the latter reproduced well under identical conditions, but since Edinburgh-bred progeny of imported flies also showed poor reproduction, a genetic difference between the two populations could be ruled out. Comparisons of the progeny of flies fed on human and rabbit blood, and of the progeny of flies fed on rabbits maintained on different diets, produced strong biological evidence for a toxicant in one of the diets which produced reproductive abnormalities in the Ft generation of flies. The trouble was thus traced to a change in rabbit diet which took place about a month before the appearance of the reproductive disorders. It is suggested that the toxicant, which remains unidentified, is concentrated by the parent female in the accessory gland secretion and thereby incorporated into larval tissues during intra-uterine development.

Descriptions are given of all growth stages of Valanga nigricornis nigricornis (Burm.). The hopper instars (normally six in the male and seven in the female) could be distinguished by the development of the external genitalia. Under laboratory conditions (mean 27–9°C and 80% r.h.), the life-cycle was completed in 6½–8½ months, and the females had a mean fecundity of 158. Crowding slowed the growth rate of the adults, extended the pre-oviposition period from 60 to 65 days at 30–9°C and reduced fecundity. It is concluded that the low fecundity and slow life-cycle preclude the possibility of the species becoming a widespread pest.

Insulaspis pinea Borchsenius, originally described from North Korea on Pinus sp., is redescribed from specimens collected in Hong Kong on Pinus taeda. A key is presented of all known Insulaspis species on Coniferae. The second species of Thysanofiorinia is described as new from Nephelium sp. (lychee) from specimens collected in Hong Kong and Taiwan.

Abgrallaspis pictor is described as new from specimens collected on Cymbidium sp.in a nursery in England. It damages the plants by causing leaf-spotting. The orchid plants were collected in North India in 1968.

Experiments in a glasshouse have shown that the most favourable conditions for transmission of cabbage black ringspot virus by Myzus persicae (Sulz.) to turnip plants with two foliage leaves were as follows: an acquisition access period of five minutes; a test-feeding period of not less than two hours; the use of nine viruliferous aphids per test plant; the use of aphids from uncrowded colonies; the use of the third leaf from the base of an infected turnip (5-leaf stage) as virus source; and inoculation of the younget leaf of a test plant. Darkening plants for 24 or 48 h did not increase susceptibility to aphid inoculation, but increased it to mechanical inoculation in the summer. When the youngest leaf was inoculated, the age of the test plants (10-25 days after germination) did not influence transmission by aphid or mechanical inoculation.

Melanagromyza bonavistae sp.n. is described from the pods of bonavist beans (Dolichos lablab) and cow peas (Vigna unguiculata) at Kawanda, Uganda. The thirdinstar larva and posterior spiracles are illustrated. Notes on the life-history are also given; two species of primary parasites and one, possibly two, species of hyperparasites have been reared.

Characteristic temporal patterns of attack by Sirex noctilio F. in Tasmania were obtained when Pinus radiata trees were either felled, completely lopped or high trimmed and girdled. Felling resulted in immediate attack whereas lopped and girdled trees were not attacked until some 9–12 days later. Felled trees were susceptible to attack for about 14 days, but lopped and girdled trees were attacked for longer periods. In some instances girdled trees remained susceptible for more than one season. Oviposition by caged S. noctilio females on healthy trees was followed by attack from wild females about 9 days later. It is shown that the timing and duration of attack by S. noctilio are correlated with the degree of stress undergone by the host tree.

Larvae of 18 species of mosquitoes were found in the region of Lake Manyara, a saline lake in Tanzania. Aedes natronius Edw., Culex tenagius van Som. and C. nakuruensis Mattingly bred in salinities ranging from 0 to over 8% NaCl; five species, including Anopheles gambiae Giles, bred only in fresh and brackish waters, while the remainder were found only in fresh water. The saline habitats were also alkaline. C. tenagius occurs only in association with hot springs throughout East Africa, but larvae were found in salinities of 0- > 8% NaCl, alkalinities of 0.05–0.32N, pH 7.8- > 11 and at temperatures of 22–42 C. C. tenagius, C. nakuruensis and C. telesilla De Meillon & Lavoipierre were new records for Tanzania, as was Ae. lineatopennis (Ludl.) collected from a nearby settlement. It is considered that the species able to breed in both fresh and salt water, namely, Ae. natronius, C. tenagius and C. nakuruensis, may comprise a complex of fresh-water and salt-water races, or even species.

The seven previously known species and one subspecies of Nephotettix are redefined, namely, N. virescens (Distant), N. nigropictus (Stål), N. cincticeps (Uhler), N. modulatus Melichar, N. malayanus Ishihara & Kawase, N. afer Ghauri and N. nigropictus yapicola Linnavuori. N. sympatricus is described as new. Nephotettix spp. fall into two groups, African (two species) and Asian (six species, one subspecies) which can be separated on genitalic characters. Distribution maps are given for each species. A key to the species based on external characters is given, but determinations should be confirmed by the genitalic characters.

Entomological investigations preliminary to a filariasis study were carried out over a period of eleven months in fourteen islands of the Seychelles group. Thirteen species of mosquitoes were found in collections of larvae from over 700 breeding places and occasional hand-catches of adults. These were: Aedes aegypti (L.), Ae. albopictus (Skuse), Ae. albocephalus (Theo.), Ae. (Skusea) sp. n., Ae. vigilax vansomerenae Mattingly ' Brown, Culex pipiens fatigans Wied., C. scottii Theo., C. simpsoni Theo., C. stellatus van Som., C. wigglesworthi Edw., Uranotaenia browni Mattingly, U. nepenthes (Theo.) and U. pandani (Theo.). Mansonia (Mansonioides)uniformis (Theo.), previously reported from the islands, was not found during the present survey.