The female sex pheromones of Chilo suppressalis (Wlk.) were previously identified as (Z)-11-hexadecenal and (Z)-13-octadecenal. This paper describes field trials of the synthetic pheromones carried out in the Philippines, Korea and Iran during 1975 and 1976. These trials established that the two pheromones in their naturally occurring ratio are attractive to male C. suppressalis in the field. Both pheromones are necessary for efficient attraction, and ratios of the two pheromones close to the naturally occurring ratio are the most attractive. The rate of release of the pheromones was found to be critical in order to obtain an attractant source comparable with the virgin female moth. The bisulphite adducts of the pheromones showed some promise as a slow-release source of attractant material with a long field life.

Preliminary experiments were carried out to assess the potential use of the two natural pheromones and of two pheromone “mimics”. (Z)-9-tetradecenyl formate and (Z)-11-hexadecenyl formate, as mating disruptants. All four compounds were shown to interfere with pheromonal communication between the sexes

Studies on the biology of Acanthomia tomentosicollis (Stål) at Ibadan, Nigeria, showed that the periods of development in the field and the insectary averaged 17 and 18 days, respectively. The hemispherical, hexagonally sculptured eggs were laid in batches of 2.99 (mean=7 eggs per batch in the insectary and 20 in the field). Preoviposition periods were 11–22 days in unmated and 6–9 days in mated females. The mean number of eggs deposited by mated females (202) was significantly higher than that deposited by unmated females (135), although the average oviposition period of 16 weeks in unmated females was three weeks longer than in mated females. Unmated males and females were longer-lived than their mated counterparts, and females generally lived longer than males. These results and other observations on 'the biology of A. tomentosicollis are discussed in the context of its seasonal biology and the pattern of infestation of pigeon pea (Cajanus cajari), its main host plant.

Field studies of predators on Aulacaspis tegalensis (Zhnt.) and laboratory breeding experiments, supplemented by taxonomic studies, showed that Chilocorus discoideus Crotch and C. bilineata Korsch. are junior synonyms of C. schioedtei Muls. and that two other forms, originally described as ‘aberrations’, may also belong to this species. Similarly, C. erythrocephalus Muls. and C. solitus Weise are junior synonyms of C. distigma (Klug). C. rufoplagiatus sp. n., allied to C. distigma, is described from the shores of Lake Victoria, and the Oriental species C. nigritus (F.) is recorded from the African mainland for the first time. C. distigma is found in the savanna and steppe areas of Africa and C. schioedtei in the forest and adjoining zones. Comparative studies suggest that, although C. schioedtei has a higher fecundity, it is not displaced by C. distigma as, unlike the latter, it is unable to breed under hot dry conditions. Comparison of host records for these two species show that C. distigma is not restricted to feeding on Diaspididae, as is C. schioedtei, but that otherwise the range of hosts and associated plants is similar for both species. The potential of these species and C. nigritus for use in biological control is discussed and it is suggested that C. schioedtei is only suitable for trial in tropical areas without a dry season, but that C. distigma and C. nigritus may be useful under a wider range of conditions.

The gracillariid leaf miner Dialectica scalariella (Zell.), which occurs in Mediterranean Europe, North Africa, the Middle East and the Canaries, is a potential biological control agent for the weed Echium plantagineum in Australia. The moth has a high fecundity and oviposits on the leaves of Echium spp. and other Boraginaceae. The larvae destroy the leaves by forming large bulbous blotch mines. There are 5-7 generations per year. Host restriction of D. scalariella to Boraginaceae was tested by exposing a wide range of cultivated plants considered to be most at risk from it because of their close relation to Boraginaceae, because they were of Australian or non-European origin, because they did not occur in the same ecoclimatic region as D. scalariella, because their entomological fauna was poorly known, and because they or related plants were known to be attacked by insects closely related to D. scalariella. The host restriction of the moth was confirmed as only boraginaceous plants were attacked. It was concluded that both in terms of effectiveness and specificity D. scalariella could serve as a biological control agent in Australia for E. plantagineum.

Examination of type specimens and other authentic material established that the earliest available name for the long brown scale is Coccus longulus (Douglas), stat. n. and that Lecanium elongation Signoret is a junior synonym of Parthenolecanium persicae (F.), syn. n. Detailed, illustrated descriptions of adult female C. longulus are given, based on collections from England, Australia, Israel and the U.S.A. Lectotypes are designated for C. longulus, Lecanium frontale Green and Lecanium acaciae Newstead. Coccus acaciae (Newstead), stat. n. is raised from synonymy and seven synonyms of C. longulus are listed.

An incomplete ring of electrocuting nets was placed round various mammals stationed singly in woodland infested with Glossina morsitans morsitans Westw. and G. pallidipes Aust. in the Zambezi Valley in Rhodesia. Catches of fed and unfed flies made on the inside and outside faces of the nets were used to estimate the number and nutritional status of flies travelling to and from the baits. The validity of these assessments was investigated by studying the responses of the flies to the netting frame, and the effects of different heights and arrangements of nets. The percentages of recently fed flies in samples leaving various mammals were: ox 33–61, donkey 51, sedated ox 42, kudu 41, washed ox 34, warthog 19, sedated goat 15, ox with three men 12, bushpig 8, buffalo 5, ox sprayed with repellent 4, bushbuck 2, goat 1, sheep 1, impala 0. With the ox, the proportion of fed flies fell by one-third when the number of tsetse attracted to the ox increased 4·5-fold to the point where the ox became intolerant. Effects of time of day and season on the proportion of flies feeding are discussed.

The genitalia and reproductive organs of a normal and of an abnormal type of cabbage root fly (Delia brassicae (Wied.)) are described. The abnormal type, possessing incomplete genitalia, was found in the Welles-bourne laboratory culture. The abnormal females were sexually attractive to males but were unable to copulate or lay eggs, whereas the abnormal males copulated but did not inseminate females. The age of females at oviposition and both larval and adult diets influenced the number of abnormal flies in subsequent generations.

The height and direction of mosquito flight related to wind speed and direction, in the absence of a host, was investigated in open savanna in The Gambia, West Africa. Non-directional suction traps (at heigts of 0·68, 2·13 and 3·15 m); directional flight traps facing four directions ar three levels (0·00–1·37 m, 1·45–2·82 m and 2·90–4·27 m) and directional suction traps facing two directions at three heights (0–1·2 m, 2·4–3·7 m nd 4·9–6·1 m) were used. Catches form the non-directional suction traps and pooled data from all flight traps at each level showed an inverse relationship between wind speed and the height of flight of Anopheles melas (Theo.), of gravid females and of male mosquitoes. There was no indication of a similar relationship for the Culex decens Theo. group or for C. thalassius Theo. The results from flight traps and directional suction traps showed that all mosquitoes were apparently flying upwind at all the levels investigaed. It is concluded that, although upwind flight probably does not occur naturally in the open at eights of more than 1 or 2 m, these experiments indicate that upwind flight could occur at higher levels, in the lee of tree and other obstacles.

Mature, singing adults of the bush crickets Platycleis intermedia (Serv.) and P. affinis Fieb. are normally separated in the field through differences in habitat preference. At some localities in southern France, nymphs and young adults of the two species occurred mixed together in herbaceous vegetation surrounding barley fields. Occasionally, there was acoustic interference between them, with modification of the song of P. intermedia. This was overcome by P. intermedia moving into the bushes and P. affinis into the barley. Cutting of the barley resulted in an invasion of the P. intermedia habitat by P. affinis so that there was further interspecific acoustic interference. Sheep grazing caused vegetation mosaics, which again created the conditions for acoustic interaction between the two species.

The distribution and host-range of Cerambyx dux Fald. are summarised, and the detailed life-history in Malta, where the hosts are apple and pear, is described. Collections of various stages from host material indicate that the duration of the complete life-cycle is three years, including a 26–28 month larval period. The number of larval instars is estimated at six. Egg survival is dependent on high humidity. The early months of larval activity are confined to the superficial regions of the trunk and main branches of the host, penetration of the sapwood and heartwood occurring later. No special air-holes appear to be constructed by the larva. No exit gallery is constructed, and the emerging adult makes use of the existing burrows, finally gnawing its way to the exterior. The period of emergence is short (8–10 days) and may be stimulated by rain. Adult life lasts about one month. The average number of eggs laid per female is approximately 13. The main predator on C. dux larvae is the larva of Zeuzera pyrina (L.). This is confined to the lesser limbs of trees in Malta, but extends throughout the trees in Gozo, and has practically eliminated C. dux from this island.

Of 11 chemosterilants tested on adult males of Ephestia kuehniella Zell., only tepa induced complete sterility. It also induced complete sterility in females of E. kuehniella. Hempa showed weak sterilising activity against adult males and had no sterility effect against the females, even at dose levels that induced high mortality. Cycloheximide induced slight sterility in the males. Carbaryl was inactive as a sterilising agent but induced some of the males to produce spermatophore sacs without mating. The latter effect was also induced in a few males by injection of tri-, penta- or hexamethylmelamines, which also induced significant infertility in eggs of untreated females mated with treated males. No structure-activity relationship existed in this group of compounds. Hemel also induced two mating aberrations: permanent copulation and sterile mating. A juvenile hormone analogue (a mixture of 3 hydrochlorinated farnesoates with activity about 1% of that of natural juvenile hormone) induced significant sterility in adult females of E. kuehniella when applied topically. It also caused 38–41% reduction in oviposition at 50–80 μg/adult. However, at 100 μg/adult, the analogue completely inhibited mating in the females. Injected doses of melatonin also caused significant reduction in oviposition. At 5·3 μg/adult, it induced most of the eggs laid to undergo incomplete development. The effects of these compounds are discussed. The sterility indices of tepa against adult male and female E. kuehniella were 19·5 and 9·2, respectively; that for hemel against males was 1·4.

Aphids of the genus Amphorophora collected from European raspberry, Rubus idaeus, have a chromosome complement of 2n(♀)=18, whereas Amphorophora from R. fruticosus agg. (blackberry, brambles) have a basic chromosome complement of 2n(♀)=20. Canonical variates analysis based on eight characters measured on numerous samples of apterous virginoparae showed that Amphorophora on European Rubus can be separated morphologically into two groups consistent with the differences in host plant and karyotype, and these two groups are concluded to be separate species. The correct name for the aphid on raspberry that is a vector of European raspberry viruses is Amphorophora idaei (Börn.), and the species on blackberry is A. rubi (Kalt.). Simple biometric methods of discriminating between A. idaei and A. rubi based on pairs of variables are suggested, and their reliability is discussed. Taxonomic problems in the European and North American Rubus-feeding species of Amphorophora are considered with particular reference to their importance in applied entomology.

Colony densities of Acromyrmex landolti fracticornis (Forel) were found to vary in habitats of introduced forage grasses in central Paraguay. Colony densities were found to be positively correlated with basal grass coverage and the amount of grazing damage. The ants preferentially harvested tender grass blades that showed little or no previous damage by other invertebrates. Colony densities and the amount of grazing damage by the ants showed negative correlations with the amount of grazing damage by other invertebrates. Preferences were determined for 13 species of exotic forage grasses. In both laboratory and field tests, Digitaria smutsii and Panicum maximum were selected significantly more often than other species, and Pennisetum purpureum, P. ciliare and Brachiaria decumbens were selected significantly less often. The preferences observed in the laboratory were also observed in field colonies. The importance of these factors in determining colony density and their practical implications on the Paraguayan cattle industry are discussed.