The influence of ageing, larval dietary nitrogen and adult carbohydrate diets on development of the male and female reproductive systems of Samea multiplicalis Guenée are described. Mature oocytes appeared in the ovarioles of one-day-old females and remained constant in number from one to three days after eclosion. Females from larvae that fed on plants of Salvinia molesta matured fewer oocytes (65 vs. 138) when the plants had lower (0·94% vs. 2·74%) levels of nitrogen. Resorbing oocytes were identified in the ovarioles of females 1–3 days old. The proportion of females with resorbing oocytes increased with age but not with larval dietary nutrition. Following high levels of larval dietary nitrogen, the seminal vesicles in males increased in length, while their width increased with age but not with diet. High levels of larval dietary nitrogen and an intake of adult dietary carbohydrate were both necessary for maximum fecundity. Higher levels of larval dietary nitrogen resulted in greater adult size, as measured by forewing length.

Cryptolaemus montrouzieri Mulsant is a well-known and historically important predator of mealybugs. It is indigenous to eastern Australia, and has been introduced throughout the world for biological control. In contrast, the other members of the genus, including those which resemble C. montrouzieri, remain poorly known. The genus Cryptolaemus, with seven previously described species, is redefined and two species-groups are recognized. The first, the montrouzieri group, comprising C. montrouzieri, C. affinis Crotch (Indonesia and Papua New Guinea and northern Queensland, Australia). C. wallacei Crotch (Indonesia) and C. simplex Blackburn (northern Australia), is revised; C. crotchi sp. n. (Indonesia) and C. sinestria sp. n. (Indonesia, Papua New Guinea and Solomon Islands) are described as new, and C. simplex is reduced to a subspecies of C. montrouzieri. A key to these species is provided. The second group comprises two of the remaining species. C. subviolaceus Crotch and C. concinnus Weise, but lack of sufficient material precludes a revision of this group at present. The final species, C. engelhardi Gorham. is transferred to the chilocorine genus Brumoides Chapin. Lectotypes are selected where appropriate.

From previous studies in Garki, Nigeria, it was deduced that the population of Anopheles gambiae Giles s.l. there includes a proportion of individuals which consistently rest out of doors and are therefore not vulnerable to insecticide residues inside houses, but may still be able to maintain malaria transmission. A direct test for the existence of such individuals in A. gambiae s.l. and A. funestus Giles in a village in Tanzania was made by catching resting mosquitoes indoors and in outdoor pits, differentially marking them according to their site of capture and releasing them from a single site. Recaptures indoors and in the pits showed no significant association between the sites of capture and recapture among the females of either species, i.e. no evidence for an invariably outdoor-resting type of female. It is concluded that behavioural polymorphism is unlikely to interfere with the successful use of house spraying for malaria control in this area. From data on the proportion of the captures found to be marked and on the parity rate, estimates were calculated of the total mosquito population available for sampling in the village.

An investigation into the possible development of insecticide resistance in Glossina was carried out by comparing the susceptibility to topical applications of endosulfan and dieldrin between two populations of G. pallidipes Austen in Kenya, one from the Lambwe Valley, where there has been a long history of spraying operations, and the other from Nkruman which has never been sprayed. Dosage-mortality regression lines and LD50 and LD95 data showed that wild-caught, non-teneral males and females from Lambwe were significantly more tolerant of both insecticides than their counterparts from Nkruman, with the exception of males treated with dieldrin. The differences were insufficiently great, however, to be incontestable evidence for the development of resistance in the Lambwe strain, although there were no other obvious sources of variability between strains adequate to account for the differences in susceptibility.

Measurements of several parameters of demographic performance for 16 field-derived Australian populations of Phthorimaea operculella (Zeller) were obtained under laboratory conditions. Fecundity, female weight and low temperature development rates were the most important parameters contributing to differences between populations. It is suggested that the increased fecundity and female weights found in warmer regions may be selected for in part by the continuous high mortality imposed by parasitoids, which have a reduced impact in the colder parts of P. operculella's range. A more rapid development rate in populations from colder areas is probably due to selection for a decreased lower threshold temperature in these areas, indicating better survival characteristics under cold conditions.

Cuticular wax was extracted from adult females of Anopheles culicifacies Giles and analysed by gas liquid chromatography. The flies were taken from pure cage stocks of three sibling species: 56 individuals of species A, 43 of species B and 51 of species C. The three cytospecies were found to be significantly different in their cuticular hydrocarbon composition by a multivariate analysis of variance. Using discriminant analysis, each cytospecies was characterized by the amounts of C25-C33 hydrocarbons extracted from the cuticle, allowing criteria to be established for the identification of flies. By these criteria, specimens from stocks of known identity were allocated to the correct group with a high success rate. These results may reflect ecological differences among the sibling species.