The inheritance of carbamate resistence in the Fc strain of Musca domestica L. was investigated by the method described by Nguy & Busvine (1960) and more than one gene, most probably two genes, were found to be responsiple for carbamate resistence. A further experiment showed organophosphate and carbamate inheritance to be linked. As it was already known that the genes for organophosphate resistence were on the third and fifth chromosome, the third and fifth chromosomal resistence factors were separated by use of marker genes. Both factors gave low to moderate levels of resistence to organophosphates and carbamates. The third chromosomal factor appeared to be associated with increased oxidative activity and the fifth chromosomal factor with a modified aliesterase mechanism. The effect of the two genes was cumulative.

A new Japanese species of Atherigona Rond., A. shibuyai sp.n., described from material reared from sugar-cane.

Specimens of seed bugs are recorded as pests of groundnuts, sorghum and cotton in Africa, usually under the name Aphanus apicalis Dall. or Rhyparochromus apicalis (Dall.). It is shown that these pests belong to the genus Naphius Stål and, further, that not all should be placed in the species N. apicalis (Dall.). A study of the genus Naphius shows that there are seven distinct species in the Ethiopian region. The true N. apicalis is shown to be the species that is known to cause damage to pumpkin in Rhodesia and sorghum in Nigeria: the pest of groundnuts in Senegal and Gambia is N. zavattarii (Mancini), not N. apicalis. To date, the other species of Naphius in Africa are not reported as pests. The known distribution of the two pest species is illustrated; N. apicalis occurs throughout tropical Africa, but N. zavattarii seems to be confined to the northern and eastern parts of Africa south of the Sahara, with the latter also present in the Canary Is, and cape Verde Is.

Virgin females of Glossina morsitans Westw. derived from pupae collected on the field were exposed in the laboratory to virgin sterile males and later to virgin normal males; the resulting productivity was an indication of multiple mating by females. Females inseminated once with sterile sperm and then held for 0, 24 or 96 hr. before being allowed to mate with fertile males produced about equal numbers of progeny 29–56 days later; however, subequal numbers of progeny were produced the first 28 days after the initial mating because of the relationship between the time of the second insemination and ovulation. Females given the opportunity to mate repeatedly for 96 hours with their first mates also mated again with new groups of males, but the incidence of this second mating was lower. Thus, multiple mating of females in the laboratory is established, but its frequency in nature is unkown.

When groups of males were exposed to successive new groups of virgin females, the minimum mean number of females inseminated per male renged from 4.9 to 5.6. However, the later inseminations were progressively less effective, and once the complement of sperm of an individual male was depleted, fertility was not recovered. The multiple mating of male and female G. morsitans is not expected to affect the use of sterile males for population control.

The increase in tolerance to topically applied chlorinated hydrocarbon insecticides shown by pregnant female tsetse flies was investigated in Glossina pallidipes. Solvent extracts of male and pregnant female flies, traeted with DDT and endosulfan labelled with carbon-14, were analysed by thin-layer chromatography and autoradiography of the developed chromatograms. No metabolites of these compounds were detected in the internal and faecal extracts. It was considered, therefore, that detoxication of absorbed insecticide was not the machanism responsible for the lower susceptibility to insecticide in the pregnant female fly. It was shown, however, by the above technique, that insecticide was absorbed by the in utero larva.

Measurement of labelled DDT absorbed by the larva was carried out by liquid scintillation counting. The results indicated that this insecticide was slowly taken up by the larva, in an amount increasing with time, and it was suggested that inert storage of toxicant in the larva is a pregnant female. This would be in addition to the effects of increase in weight and other possible physiological factors.

The examination of samples of Antestiopsis orbitalis (Westw.) from different parts of South Africa has shown complete intergradation between the colour patterns of the typical subspecies and that of the form facetus (Germ.), hitherto of indeterminate infraspecific status, and the latter name is suppressed. Additional localities of ocurrence are given for A. orbitalis, and Antestia rufovittata Dist. is redescribed and transferred to Antestiopsis.

The natural moth emergence-pattern of Diparopsis castanea Hmps. from non-diapause and diapause pupae is described for Malawi and Rhodesia and related to the growth of the cotton plant. Pupal populations and mortality in the field are assessed and the location of pupae in the soil for both ridged and flat land is determined. The effect of temperature on the development of diapause pupae is investigated. Temperatures both above and below 75°F. are shown to cause inhibition of pupal development. The investigations show that it is possible to effect a major alteration in the period of moth emergence from diapause pupae by burying the pupae to a depth of eight inches and thus avoiding heat inhibition. In this way, the majorrity of moths emerge before the cotton crop is able to support an infestation. Attempts to achieve this effect with a natural field population of pupae failed and further investigation is required. Heavy grass mulches are shown to inhibit pupal development possibly throgh reduction in soil temperature and retention of soil moisture.

Argyrostagma niobe (Weym.) suddently appeared as a defoliator of wattle in 1955 in the Turbo area of Eldoret District, Kenya, and spread in this area and outbreaks also developed in two other isolated areas, at Sotik and on the Mimosa-Nandi Border. Study of the life-cycle, of which the various stages are described, revealed a number of causes of mortality of which the initially most promising for control were parasites and a predatory Pentatomid, Glypsus conspicuus (Westw.). None of these, however, increased greatly above their first recorded level of incidence and the population of A. niobe was eventually controlled by a naturally-occurring nuclear polyhedrosis. This disease was found to be transmissible in the laboratory by allowing larvae to feed on foliage sprayed with suspensions of polyhedŕa whilst an indication that this could also be done in the field was obtained in one experiment.

Chamical control presented a number of difficulties, the chief arising from insufficient dispersion of the spray through the canopy of tall trees and the failure of small droplets finally adopted consisted of an application of endrin applied at a rate of 2–4 oz. active ingredient per acre in 2 gall. diesolene. This was satisfactory when applied to yonug trees through a Micron sprayer, and to trees of all heights by aerial boom sprayers. This mathod of control is only suitable where complete elimination of a population is necessary, such as in a new outbreak area, as the costs are too high to permit frequent applications.

Dasychira georgiana Fawc. was recorded in small numbers at about the same time that A. niobe was first recorded, but the population did not build up to serious proportions. Its life cycle, of which the various stages are described, was broadly similar to that of A. niobe but natural agents of control, chiefly the pupal parasite Compsophorus fumosus (Morl.) (Ichneumonidae), were usually effective in keeping the population in check. The reason for the success of this parasite, as compared with those of A. niobe, is not known. The larvae were successfully controlled with the same endrin spray as was used for A. niobe.

Pupulations of the West African cocoa capsids Distantiella theobroma (Dist.) and Sahlbergella singularis Hagl. were sampled in 1966–67 by several methods: fast knockdown over sheets with pyrethrum, mercury-vapour light-trap, direct counts in a small artificially established area of high population, and observations of presence or absence in randomly selected inspection squares.

A population build-up in mature cocoa accompanies and probably directly depends on development of the main crop from July or August to October. When pods become scarce after harvesting there is in S. singilaris a period of dispersal in which the species becomes more widespread as feeding is transferred to vegetative tissues, and in D. theobroma a more local change of feeding sites.

Subsequent events vary greatly between areas and between years. It is suggested that the extent to which capsids are able to utilise vegetative tissues varies and depends on nutritional changes in the external parenchymatous tissues from which their food is obtained.

Low humidities during spells of harmattan in January and February almost certainly kill larvae in exposed situations, but feeding conditions following such periods may be particularly favourable to capsids as large rapid population increases can occur locally. The factors involved are obscure but may be related to processes of regeneration stimulated by leaf loss and other damage in dry conditions.

The densities and seasonal patterns found are discussed in relation to results of previous workers and some implications for control briefly considered.

In a laboratory investigation in Rhodesia of the ability of Glossina morsitans Westw. to digest blood from the impala (Aepyceros melampus), the efficiency of digestion, as measured by the regression of the amount of haematin excreted in 48 hr. on the size of the blood meal, was found not to differ significantly between flies fed on impala blood and flies fed on blood from a variety of vertebrate hosts. This result, together with the report that captive flies can be induced to engorge from a live impala, refuts the suggestion that the low incidence of impala blood meals recorded in the firld is because impala blood contains a facor lethal to tsetse. One possible reason for the non-utilisation of this antelope, despite its abundance in tsetse areas, is its vigorous reaction to biting insects.

Two series of all-night hourly catches of Mansonia (Mansonioides) uniformis (Theo.) on the verandah of a house and at an outdoor open site with man as bait and a third series at the same outdoor site with calf as bait were carried out during 1960–62 on an open mixed rubber and coconut estate overlooking a swamp, in Aggona, a village three miles south-east of Colombo. The physiological age of the mosquitos captured was determined by a count of the follicular relies in the ovarioles.

The mosquitos were active only at night; the biting cycle on human bait showed two peaks in both situations—a well-defined early peak and an irregular late peak on the verandah and a minor early peak and a larger lat peak at the outdoor site. In the verandah series the two oldest age-groups, 2-parous and 3-parous females, showed more activity during the second peak, while in the outdoor series the oldest age-groups were most active during the early peak, a result suggesting a difference in behaviour on the part of the older females compared with the overall population in both situations. M. uniformis was strongly attracted to cattle bait; much activity was recorded at this bait site during the first four hours of the night.

Age-composition of the populations in all three series was found to be similar irrespective of the site and bait used. The results were more or less constant from month to month in spite of weather changes. Daily mortality of M. uniformis taken at the two baits was similar and showed consistency from month to month.

A large proportion (73.4%) of females returned to feed directly from oviposition.

The damage caused by the larvae of four Melolonthine and one Ruteline scarab species to four grasses and Trifolium repens grown in pots was examined for interactions between species with and without manure added to the soil. Only slight interactions between scarab species and plant species were detected in the damage to pastures, and these were caused by a differential insect response to Trifolium. Most scarabs damaged Trifolium as much as they damaged the grasses, but Anoplognathus sp. appeared to avoid Trifolium in the absence of manure. Sericesthis geminata Boisd. caused more damage to Trifolium than S. vigilans (Sharp) or Rhopaca magnicornis Blkb.

The addition of manure to soil reduced to negligible proportions the damage to all pasture species except Phalaris tuberos, which suffered significantly greater reduction of foliage than other plants in the presence of manure. The highly significant alleviation of damage by manure occured with all scarab species except S. vigilans, which did not cause damage even in the absence of manure.

In this short-term experiment survival and pupation were not influenced significantly by plant species or manure.

The biology of three West African ambrosia beetles, Trachyostus aterrimus (Schauf.), T. ghanaensis Schedi and T. schaufussi schaufussi (Strohm.) is described on the basis of studies made in China and Nigeria, and notes are given on the six other species and subspecies of Trachyostus that have been taken in West Africa.

All species of Trachyostus are confined to forest areas in West Africa. some of the species extend into montane and swamp forest, but the genus is most abundant in lowland rain forest. It is suggested that susceptibility to desiccation of the young larvae and of the ambrosia fungus is the principal factor in limiting Trachyostus species to forest areas. Two species, T. ghanaensis and T. interstitialis Schedl, are confined to the forests between Sierra Leone and Ghana, but the remaining species are found throughout the lowland forest of west Africa.

Host selection by species of Trachyostus depends mainly on the taxonomic status of the host, the condition of the tree, and the time of year. The genus as a whole is considered very selective. T. ghanaesis attacks living trees of only one host species, selecting individual trees and favouring the most vigorous. All other species of Trachyostus normally attack felled trees of a wide range of host species, but show preferences for those of a small number of plant genera. Attack on living trees by species other than T, ghanaensis occurs in the dry season. It is suggested that T. ghanaensis is sensitive to subtle changes in tree condition, while the remaining species require a more drastic change before attacking such trees.

The process of nest initiation and establishment is described for ome species. Species of Trachyostus differ from other tropical Platypodids in that the length of time elapsing between nest initiation and the emergence of the first young adults is exceptionally long. This is thought to be mainly due to the ambrosia fungus requiring a long time to establish itself on the gallery walls of the nest.

All species of Trachyostus are active in daylight hours. Emergence of young adults from the nest occurs only in daylight and is dependent on a drying atmosphere. Falling light intensities probably contribute towards ending emergence in the late afternoon. The thresholds of humidity and illumination for emergence of T. schaufussi schaufussi appear to be higher than those of T. aterrimus.

Nests of T. aterrrimus and T. schaufussi schaufussi remain functional for about nine months, but those of T. ghanaensis can still be active after four years. The protracted nest duration of T. ghanaensis is apparently a consequence of the habit of this species of attacking living host trees in which the rate of development seems to be slowed down. Only a small proportion of the nests initiated by species of Trachyostus are successful. In T, ghanaensis this high failure rate is attributable to failure of the ambbrosia fungus, but in the other species insect nest-associates and predators are apparently the main causes.

The habits and life-history of T. ghanacnsis can only be compared with those of one other Platypodid, Dendroplatypus impar (Schedl), a Malaysian species. Both species attack only living trees, and show a high degree of host selection. The intensity of attack on the host tree by these species is very low, and the life-cycle of each seems to take a long time for completion.

Intensive surveys for breeding places of anopheline mosquitos have been carried out in Israel since 1948, and have proved to be very effective for following the dynamic changes in anopheline populations. An account is given is given of the situation with regard to the breeding of anopheline mosquitos in Israel between 1963 and 1965, in the final stage of the malaria eradication project. During this period only nine of the 14 species of Anopheles recorded in Israel were found, and of these A. sergentii (Theo.) and A. superpictus Grassi were the most abundant.

About 85 per cent. of the breeding places were found in the northern part of the country. Fifty-four per cent. of the breeding places in the whole country were man-made. Seventeen per cent. of the 1330 samples of larvae determined contained larvae of more than one species. The distribution of different species in various biotopes and the seasonal variation in the number of breeding places of malaria-transmitting anophelines are also described.

A. sacharovi Favr., the most important malaria vector in the past, has not been found in Israel since 1960. The observations on A. sergentii suggest that an exophilic strain of this species has been selected in Israel. A. coustani Lav., hitherto a rare species, has been found breeding more frequently in recent years.

The information collected during 1963–1965 is discussed for each species.

Observations on biological variablity of pupae of G. morsitans Westw. collected in the field, and effect on eclosion of the adult fly due to temperature, light and gamma-radiation are reported.

The homogeneity of eclosion from wild pupae varied during the year owing to variations in pupal viability. Emergence was lower in the warmer months September to December than in the cooler ones, May to August, and in one season low eclosion rates were connected with a high proportion of runts, although another analysis revealed no correlation.

Gamma-radiation redused eclosin by killing all pupae treated during their first ten days after larviposition. MOrtality of male pupae was increased by irradiation between the 15th and 13th day of pupal life, while eclosion was apparently normal with treatments given between the 16th and 29th day. Weight losses indicated that five- to ten-day-old pupae possibly did not die before the 30th day after larviposition while younger pupae containing fourth-instar larvae at the time of treatment were killed either immediately or by the 15th day.

Diurnal emergence from wild pupae in the laboratory showed a peak during the afternoon (1400–1730 hr.) which was not affected by light or gamma-radiation. In the field, eclosion occurred primarily between 15° and 27°C. and was apparently inhibited by higher and lower temperatures. Relative humidity did not appear to be involved in the timing of emergence.

Recognition in 1963 in central Queensland of the Ridgelands strain of Boophilus microplus (Can.), resistant in varying degrees in laboratory tests to all acaricides commercially available in Queensland, Australia, led to spraying trials on cattle with these acaricides to assess their effect on the resistant strain. Dosage mortality tests on larvae exposed in acaricide-impregnated filter papers, indicated the following levels of resistance, carbary 13×, carbophenothion 17×, coumaphos 1.6×, diazinon 19×, dioxathion 7.2× and ethion 2.7×.

Stalled cattle infested with either susceptible Yeerongpilly or resistant Ridgelands ticks were sprayed with the recommended concentration of commercially formulated acaricide. Efficiency of treatment was determined by comparing the number of ticks falling from sprayed and unsprayed cattle. Coumaphos (0.025%) and ethion (0.075%) produced efficient control of the resistant strain, but carbophenothion (0.086%), diazinon (0.05%) and dioxathion (0.075%) allowed considerable numbers of the resistant strain of ticks to survive. Carbaryl (0.3%) as a melt-type formulation gave inconsistent results and possible reasons are discussed. Poor control of the resistant strain was largely due to failure to kill the nymph stage.

There was general correspondence between the resisdence level determined in laboratory tests and the degree of control achieved in spraying trials. However, the reletively small difference between resistence levels of 2–3× (coumaphos and ethion) and 7× (dioxathion) was critical in the practical control of resistant ticks on cattle.

The following chemicals gave excellent control of the Ridgelands strain in spraying trials on stalled cattle: bromophos (0.15%), bromophos ethyl (0.1%), chlorfenvinphos (0.06%), chlorxylam (0.5%), Ciodrin (0.1%) Dursban (0.025%), fenchlorphos (0.2%), GS13002 (0.05%), Imidan (0.075%), methidathion (0.05%) and SD8448 (0.025%). Malathion (0.5%), prothidathion (0.075%), macarbam (0.075%) and RD12308 (0.2%) controlled the Yeerongpilly but not the Ridgelands strain. Arsenic (0.2%) produced about equal mortality in both strains, but was clearly a less efficient acaricide than organophosphorus chemicals.

Rice tungo virus is tranmitted by Nephotettix impicticeps Ishihara but not by the closely related N. apicalis (Motsch.). Hybrids have been obtained from crosses between these two species. The morphological characteristics of the hybrids were not identical with either parent in respect to the marking on the abdomen of the nymphs, the submarginal black band on the vertex of the adults, or the number of teeth on the ventral surface of the aedeagus of the male genitalia. However, more than 10 per cent. of them, regardless of stage of development or sex, were able to transmit the tungo virus, indicating that the transmissive ability is inherited even in an interspecific cross. The virus seems to be nonpersistent in the hybrids as it is in N. impicticeps.

A life-table and age-specific fecundity schedule are given for females of Glossina austeni Newst. maintained on lop-eared rabbits. From these the innate capacity for increase in numbers (τm) is calculated, from two sets of data, as 0.0166 and 0.0155 per day, respectively. These values are better than previously obtained for Glossina and it is concluded that as such they were mainly due to the excellent nutrition of the flies. A colony in which all female offspring produced are added to the breeding stock is referred to as being in the ‘expanding phase’. The stable age distribution that would be established in a rabbit-fed colony of G. austeni in the expanding phase and the expected rate of increase in numbers of the colony when the stable age distribution exists are calculated from the value of τm.

The characteristics of a colony of G. austeni in the ‘stationary phase’, when only those offspring required to maintain the colony at a constant size are retained, are described. It is concludef that a stationary colony of y adult flies would have a disposable output per week of 0.277y young adult males and 0.233y young adult females. Some implications of these findings in relation to the sterible male techinque for tsetse control are briefly discussed.