Collections of siricid-infested coniferous trees were made in 150 localities in 19 European countries, Turkey and North Africa to obtain parasites and parasitoids of siricids for use in the biological control of Sirex noctilio F. in Australia. During this work, information was obtained on the distribution and biology of 8 siricid species (S. noctilio, S. cyaneus F., S. juvencus L., Urocerus augur (Kiug), U. gigas. (L.), U. sah (Mocs.), U. fantoma (F.), Xeris spectrum (L.)) and 7 parasitoids (Rhyssa persu.asoria (L.), R. amoena. Gray., Pseudorhyssa maculicoxis (Krchb.), Megarhyssa emarginatoria (Thnb.), Ibalia leucospoides leucospoides (Hochenw.), I. rufipes drewseni Borries, Odontocolon geniculatum. (Krchb.)). Data are presented on distribution, flight periods and sexratios (determined from emergence records), factors leading to the susceptibility of timber to siricid infestation and the types of timber and host tree species infested. Levels of parasitism by the various parasitoid species, determined from emergence records, are given. Localities are assigned to bioclimatic categories, and their siricid and parasitoid species are classified in relation to the climatic criteria. The ecological status of S. noctilio is discussed in relation to its establishment in Australia.

In laboratory experiments in Australia under standard conditions, densities of the dung beetle Euoniticellus intermedius (Reiche) exceeding 150/1-litre pad of cattle dung were shown to suppress breeding of Musca vetustissima Wlk. The experiments also suggested that it was the effect of dung disturbance on the survival of eggs of the fly that led to suppression. Natural vaiation in the quality of cattle dung obscured but did not alter the effects of high beetle densities. The mobility of M. vetustissima in particular, obscured the relationship of its abundance to dung beetle numbers in the field in 1974–75 and 1975–77 an intial high level of flies was apparently reduced and suppressed by a seasonally late but otherwise similar level of beetle attack on dung pads.

During a large-scale air-spray trial using endosulfan against Glossina morsitans centralis Machado in the Okavango Delta area of Botswana, a programme of ageing all flies caught on fly-rounds was undertaken. The aim was to evaluate closely the effect of repeated sprays on the population and especially to determine the origin of the small residual population that often remains after spraying. Ageing males by the wing-fray method indicated that none survived the spraying. Ageing females by ovarian dissection showed that (a) no breeding occurred between sprays, (b) one pupal period was just covered by four spray applications, (c) the residual population was composed of females that had survived the spraying and (d) all survivors had been pregnant at the time of treatment. Dissections also showed a very low rate of insemination between sprays, but the few females that survived spraying were all inseminated. Larval and pupal periods under natural conditions of fluctuating temperature are discussed together with methods of improving air spraying results by eliminating pregnant females.

Approximately 300 000 larvae of Phthorimaea operculella (Zell.) infected with granulosis virus were collected from virus-treated potato crops in Western Australia. Modified crop culture and releases of laboratory-reared adults were used to boost the natural populations. Virus was applied as an aqueous suspension of pulverised diseased larvae. Infested foliage was collected into large polythene bags; the larvae were forced from their mines by heat and collected by washing in water. Collection and extraction took 100 h; field propagation of virus is thus inexpensive. The purification of the virus was carried out by differential centrifugation and separation on sucrose gradients. A total of 35 g of pure freeze-dried material containing approximately 1·35×1015 particles was obtained.

A silicone membrane was developed to meet the feeding requirements of Glossina palpalis palpalis (R.-D.). Starting with a total of 1050 females, a self-sustaining colony fed on defibrinated pig blood was established. The colony performance in terms of mean daily mortality, mean pupal weight and fecundity was evaluated. With the exception of June 1976, the mean daily mortality ranged between 0·40% and 1·20%. During June 1976, bacterial infections caused a sudden increase in mortality. Escherichia coli and Staphylococcus spp. were predominant in the gut of dead and diseased flies. Pure cultures of either organism caused the same symptoms in teneral flies within one week after uptake of an infected blood-meal. The weight of the offspring significantly decreased with increasing female age. Starting with a mean pupal weight of 30 mg there was a decrease of 4–6 mg over a period of 90 days. The innate capacity for increase in numbers (r-) was calculated based on data from 340 females. The value of rm = 0·0095 would result in a 32-fold increase of the colony in one year.

Many West African mosquitoes fly at low levels when crossing open country. Experiments were therefore conducted in the Gambia on the effect of high fences on their dispersal. In the first experiment, a circular mosquito-proof fence 2·9 m high and with a radius of 18 m was constructed. Catches inside on human bait of Mansonia spp. were about 60% lower than catches outside the fence, whereas catches of Anopheles spp. in the two sites were not significantly different. In unbaited suction traps, catches of Mansoniainside the fence were significantly lower in traps 0 and 0· m above the ground, but not at 1 to 3 m, than in traps at similar levels outside. This suggested that, after flying over the fence, mosquitoes had not resumed normal ffight levels by the time they were trapped in the centre of the circle. In a second experiment, a much larger fence was erected, 6 m high and with a radius of 65 m. Catches were conducted in experimental huts in the centre of the enclosed area and at a distance of 70 m outside it when the fence was erected and again after its removal. Catches of Mansonia spp. on human bait in the hut inside were 46% of the total catch in the two huts when the fence was erected and 48% after its removal; catches of Anopheles spp. (A. gambiae Giles and A. funestus Giles) were 43% with, and 53% without, the fence. In calf-baited light-traps, catches of Mansonia were 41 % of the total with, and 38% without, the fence, and those of Anopheles 58 and 44%. Thus the presence of the 6·m fence had no significant effect on the density of mosquitoes in the centre of the enclosed area, and it is concluded that mosquitoes were flying freely over it. Due to the prevailing low winds in the area, passive transport of mosquitoes over the fence by the wind was not thought to be important.

The tick infestation patterns observed during 1966–73 are described for wild animals and cattle on the northern plateau of north-eastern Zambia, the eastern plateau and the intervening Luangwa valley. The seasonal periodicity of adult Amblyomma sparsum Neum., as observed on buffalo, was similar to that of A. variegatum (F.). Five major depart ures from the patterns of infestation previously found in the Central Province were observed. Boophilus decoloratus (Koch) was partially or totally replaced on cattle by B. microplus (Can.).Rhipicephalus appendiculatus Neum. although present on wild fauna in the valley, was absent from cattle on the eastern plateau. R. evertsi Neum. was absent from much but not all of the northern plateau and occurred in very low numbers only on the cattle of the eastern plateau, yet was present on the wild fauna of the Luangwa valley. Hyalomma marginaturn rufipes Koch was practically absent from cattle on the northern and the eastern plateaux and from the wild fauna, except buffalo, of the valley; H. truncatum Koch was abundant on cattle on the northern plateau and on the wild fauna of the valley, but on the eastern plateau cattle it occurred in low numbers only. A. pomposum Dön, was found on cattle in one area of the northern plateau, the only specimen of Amblyomrna on that particular herd. These anomalous findings are discussed in relation to the situation elsewhere in Zambia and in neighbouring territories.

Adults of Hydrotaea irritans (Fall.) in south-western Scotland were caught in a Manitoba trap and a black suction trap baited with carbon dioxide. Trapped flies were dissected to investigate their reproductive condition, their blood feeding activity and whether they were newly emerged. Trapping of the first gravid females in August was accompanied by a sharp decline in adult activity. The proportions of females in the various ovarian categories suggested that there is a preliminary phase before host-seeking begins, attraction to animals during most of the cycle and a behavioural change at the end. Females with eggs at stages I, II and III accounted for 94% of all females caught; the only females with blood in the gut were in these categories. Some males also were obviously blood-fed. There was a single mating period lasting five weeks. Inseminated females were first trapped in the third week of July, when the numbers of males started to decline, and within five weeks all females trapped were found to have been inseminated. After this, no more males were caught. Only females with eggs in stages later than stage II of the first ovarian cycle were inseminated. H. irritans was univoltine, with two but not three complete ovarian cycles during the summer. There was no difference in feeding or reproductive development between flies from the two traps.

Dissection of 2337 female Glossina morsitans morsitans Westw., collected over an 11-month period (118–420 per month) from a game reserve in Zambia, revealed that abortion is a regular feature of tsetse reproductive biology and apparently the most frequent reproductive abnormality in the tsetse population. It occurred among ifies in all ovarian cycles from 1 to 7+4n (minimum age 10–80 days) and apparently involved all pregnancy stages. Neither follicular degeneration nor egg retention was encountered, suggesting that these particular reproductive abnormalities are infrequent in nature.

Samples of 25 African populations of Aedes aegypti (L.) were examined for variations in scale-colour pattern of palps, halteres, abdominal tergites and metatarsi and in larval body colour. A colour index based on these characters showed domestic populations to be paler than populations found in forests. Classification of phenotypic and genotypic variations in the amount of pale scaling on palps, halteres and, especially, tergites revealed statistically significant differences between some of the populations. Although it was impossible to identify individual mosquitoes, population samples could be identified according to subspecific designations as A. a. formosus (Wlk.) and A. a. aegypti.

Low fecundity in the laboratory was found in populations of Aedes aegypti (L.) exhibiting Black tergite (Bt), a phenotype characteristic of the feral A. a. formosus (Wlk), whereas high fecundity was found in six domestic populations of A. a. aegyptiin which the phenotype was absent. An investigation of the cause of low oviposition by the feral population indicated that behavioural differences in mating and feeding were not responsible; egg retention was identified as the major factor. Introduction into laboratory procedure of a variable simulating the feral environment, i.e., coconut-shell infusion at the oviposition site, induced a highly significant increase in feral fecundity both through its chemical constituents and visual attraction. Differential response to oviposition site is discussed in relation to the evolution of subspecies of A. aegypti.

Tomato yellow leaf curl virus (TYLCV), which is transmitted by Bemisia tabaci (Gennadius), is a very destructive disease of tomato i Israel. Soil mulching with yellow polyethylene sheets delayed the spread of the disease for at least 20 days. In laboratory and field experiments, B. tabaci was found to be more attracted to yellow polyethylene than to straw or to aluminum- or blue-coloured polyethylene. A combined treatment of mulching with yellow polyethylene sheets and 1% sprays of azinphos-methyl starting 20 days after germination was the most effective in preventing the spread of TYLCV.

All available records showed that Eldana saceharina Wlk. occurs in wild plants in all suitable areas of Africa south of the Sahara. Until a few years ago, it was only of economic importance in West Africa as an occasional pest of maize and sugar-cane, but a crop-feeding form has recently appeared in East Africa. Biological studies were carried out in the field and laboratory at Kawanda, Uganda, between 1970 and 1972 using natural and artificial larval diets. The life-cycle lasted 2–3 months, depending on temperature, and the number of larval instars depended partly on the diet. The adults lived for two weeks, during which time the females each laid 400–600 eggs. The majority of eggs and small larvae were taken by ants, but sufficient larvae survived to cause considerable damage. The pupae and larger larvae lacked efficient natural enemies in East Africa, and the introduction of parasites is suggested to prevent serious crop damage. The relatively evenly spread rainfall at Kawanda allowed maize to be planted every month so that field populations of E. saccharina and the other stem-borers Chilo partellus (Swinh.), Busseola fusca (Fuller) and Sesamia calamistis Hmps. could be studied throughout the year. Collections from maize, sorghum and sugar-cane showed that, although the four species attack the same host-plants, they occupy different ecological niches.

A series of investigations was conducted to evaluate the comparative attractiveness of cattle, sheep and goats to Glossina morsitans morsitans Westw. and G. pallidipes Aust. in the Zambesi Valley, Rhodesia. It was shown that cattle are subjected to in excess of three times the challenge by male G. m. morsitans than either sheep or goats. Due to the repellent effect of man's presence on the attraction and feeding of female G. m. morsitansand both male and female G. pallidipes on the bait animals, no rational relationship could be postulated for them. Possible factors accounting for the difference of attractiveness between the three bait species are discussed.

The comparative attractiveness to Glossina morsitans morsitans Westw. and G. pallidipes Aust. of donkeys, cattle, sheep and goats in the presence of wild game was examined during two investigations in a middle-veld area of Rhodesia. Host preferences were assessed by the identification of blood-meals collected in the grazing area. Both cattle and donkeys provided a high proportion of the diet. Sheep and particularly goats were fed upon to a minor degree. The significance of the findings is discussed in relation to tsetse control.

A key is provided to the eight genera of Anomaloninae occurring in Melanesia. The Anomaloninae are endophagous parasites of Lepidoptera and Coleoptera larvae. The Melanesian species of Anomalon Panzer, Trichomma Wesmael,Heteropelma Wesmael, Therion Curtis, Pseudanomalon Szépligeti, and Aphanistes Foerster are keyed and discussed. A total of 21 species is recognised of which 11, Trichomma cheesmanae sp. n., T. pacificum sp. n., Heteropelma hirsutum sp. n., Therion unguiculum sp. n., A phanistes nexus sp. n., A. luscus sp. n., A. limulus sp. n., A. dnopherus sp. n., A. paupus sp. n., A. sedlaceki sp. n. and A. anaxeussp. n., are described. An Australian species, Anomalon, morleyiGauld, is recorded from Melanesia for the first time. Trichomma elegantulum Turner is placed as a junior synonym of T. clavipes Krieger.

Samples of larvae of Aedes aegypti (L.) were collected in three principal habitats, domestic, peridomestic and feral, in the Rabai area in eastern Kenya. The samples from the domestic habitat represent the population of the domestic form, A. a. aegypti, and the feral samples from tree holes from Bejumwa Forest represent the feral subspecies, A. a. formosus (Wlk.). The peridomestic samples from steps cut into trunks of coconut palms most probably represent hybrids between the domestic and the feral forms. These samples were brought to the laboratory where they reproduced in high numbers, and crosses were made between the three populations. Adults of the parental populations and those resulting from the crosses were marked with different colours of fluorescent pigments, released in the peridomestic habitat in the Rabai area and subsequently recaptured in biting catches on man in the domestic and peridomestic habitats. The results indicate that domesticity, particularly house-entering behaviour, in A. aegypti is genetically controlled and is a product of the action of several genes. The gene action in terms of house-entering behaviour is additive as can be clearly seen from the recapture data for the various crosses. The percentage entering houses was highest among mosquitoes of the form from inside houses (the domestic A. a. aegypti population (D)) and the percentages decreased progressively through the peridomestic (P) and hybrid forms to the feral population of A. a. formosus (F) in the following manner: D (45·)DP (15 ·5), PD (13·9), P (9·8), DF (5·7), FD (73·), PF (1·5), FP. (0·6) and F (0·6).The recaptures outdoors were in the reverse order, the highest percentage being for F (187·) and the lowest for D (8·5), DP (8·0) and PD (7·7). The data suggest that the larvae from the peridomestic habitat may represent hybrids between the domestic and feral forms

A model for the inheritance of behavioural characters in mosquitoes is presented. On the basis of isolating mechanisms and partial hybridisation, it is concluded that A. a. aegypti and A. a. formosus have developed as geographically isolated allopatric populations. This supports the existing polytypic concept of speciation in A. aegypti. Spatial distribution, non-random mating and the existing series of isolating mechanisms indicate that the domestic type form has been introduced into East Africa, most probably on ships.