Puri has divided the Indian Anopheline larvae into two divisions and four groups according to the character of the pleural hairs. The following is a study of the larvae of some South African Anophelines on the same lines.

Spring migrants of Myzus persicae (Sulz.) may be produced either by parthenogenetic aphids derived from fertilised eggs laid on the primary host, or by parthenogenetic aphids overwintering on secondary hosts. Five variates, based1 on eight morphological characters of alate M. persicae, are examined to investigate how to distinguish between alatae derived from populations that have overwintered by these two means. No single variate is adequate to identify correctly all specimens, although two of them, number of abdominal tubercles, and shape of the fenestra in the central abdominal patch, may each correctly assign as many as 90%.

The daily oviposition rhythm of the tea red spider mite, Oligonychus coffeae (Nietn.) under laboratory and field conditions is described. In the laboratory, the oviposition rate was steady under constant light or darkness, but under alternating light and darkness (LD 12:12 and 8:16) showed peaks soon after the change from light to darkness and vice versa. Under field conditions, oviposition peaks occurred at dawn and at dusk when there is a rapid change in light intensity.

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.

A method of rearing large numbers of Aëdes aegypti for the biological assay of insecticides is described. The larval food found to be most satisfactory was a breadcrumb infusion. Blood is necessary for oviposition (human blood is best), but the main batches of insects destined for spraying are fed on water, sugar and raisins.

This work is being carried out under a grant from the Medical Research Council. The authors are grateful to Prof. P. A. Buxton and Dr. V. B. Wigglesworth for advice and encouragement.

The purpose of this paper is to present the more important features of the internal anatomy of a subterranean viviparous mealy-bug commonly found on the roots of clover in the eastern part of the United States. Only the female was studied, since the male has never been found. No attempt was made to present many of the details which were found to resemble homologous parts of the common oviparous mealy-bug, Pseudococcus citri, Risso, as described by Berlese in 1893.

Investigations were carried out on the ecology of Aedes (Aedimorphus) dentatus (Theo.) in the Ngong Forest near Nairobi between 22 June and 10 September 1971. Five 24-h collections on human bait showed that Ae. dentatus is predominantly a daytime biter with a peak of activity around sunset. At the time of its greatest activity none came to bite on the 7- or 10-m platforms. Of 94 blood-meal specimens, 50 were of Bovid origin (cattle), 18 from unidentified Bovids, 13 from unidentified mammals, one from a bird, three from any primate and nine did not react with the antisera used. Resting adults were frequently found underneath leaves of Hypoestes verticillaris, a herb which grows in partly shaded areas in the forest near the forest edge. A few adults came to bite in a house outside the forest not far from the forest edge. Breeding places were not found. The evidence for Ae. dentatus being a vector of yellow fever is inconclusive. The 33 other species of mosquitoes collected are listed.

I have recently received a tube of thrips from the Government Entomologist, Coimbatore, found to be badly damaging tea on an estate near Kotagiri (altitude 6,500 ft.), in the Nilgiri Hills, S. India.

Greenhouse whitefly, Trialeurodes vaporariorum Westwood, is one of the major insect pests of agricultural crops such as eggplant. Due to various difficulties associated with synthetic pesticides, more environmentally friendly alternative methods are greatly appreciated for controlling pests. In the present study, the induction of resistance was investigated in eggplant using root and foliar application of jasmonic acid, abscisic acid, as well as Nesidiocoris tenuis (Reuter) either individually or in combination against T. vaporariorum. The experiments were carried out under laboratory conditions inside a growth chamber, which was set at 27 ± 2°C, 50 ± 5% relative humidity with a 16 h day length. Our results showed an increase in plant resistance due to the higher immature mortality rates, longer immature periods, lower longevity of adults, and fecundity. In free-choice situation, oviposition on root jasmonic acid (RJA) + N. tenuis and root abscisic acid (RABA) + N. tenuis was similar, but numbers of eggs deposited on these plants were lower than other treatments and control plants. The plant enzyme activity and phenolic content were significantly greater in RJA + N. tenuis and RABA + N. tenuis, intermediate in individual treatments, and the lowest in control plants. Correspondingly, T. vaporariorum longevity, number of eggs produced per female, oviposition preference, all were lowest when the insects fed on these treatments. These findings suggest that the induction of resistance in eggplants with the physiological changes in the host plant leads to a reduction in whitefly damage.

An operation is described in which approximately 100 sq. miles of heavily infested tsetse country in Southern Rhodesia, supporting both Glossina morsitans Westw. and G. pallidipes Aust. and an abundant and varied game population and formerly an area of endemic sleeping sickness attributable to Trypanosoma rhodesicnse, received six applications of 4 per cent, γ BHC in diesolene, discharged from aircraft in the form of a coarse aerosol, between May and September 1957. The area was a valley bounded by an escarpment, which provided conditions of relative isolation.

Fly-round catches of G. morsitans taken before, during and after the operation indicated that in those parts of the area that had received uniform treatment an estimated reduction in population, after the final application, of between 96·6 and 100 per cent, had been achieved, but where only the vegetation forming the riverine fringes had been treated the reduction was less. Quantitative data on the effect of the treatment on G. pallidipes were not collected, but the species ceased to be found in an investigation on sampling techniques that had been in progress in the area.

The area had been chosen for a resettlement scheme of indigenous people that was due to begin before October 1957, and the purpose of the spraying operation was to reduce the population of tsetses to a level that would permit the introduction of the people and their stock with comparative safety from trypanosomiasis. It was hoped that the number of people to be resettled would be sufficient to clear most of the tsetse habitat in their text-abstract agricultural activities and that the tsetses would be permanently excluded from the valley. Four to five years after the start of resettlement there were still several uncleared areas remaining, but the situation was continually improving, and estimates in 1962 indicated that the population of G. morsitans had remained at a low level, showing a reduction of between 81 and 100 per cent, as compared with that prevailing before the spraying operation. The stock introduced in 1957 were maintained under drug treatment, and the rate of infection with T. congolense was kept below a 3 per cent, level; no cattle died from trypanosomiasis, and their numbers had more than doubled by 1962. No case of sleeping sickness occurred.

The work described here showed that, under conditions of relative isolation, G. morsitans can be sufficiently reduced in numbers by means of an insecticidal aerosol discharged from aircraft to permit the successful introduction of people and stock, provided that adequate veterinary supervision is given, and that under these conditions settlement can prevent the recovery of a population of this species.

Larvae of the robber fly Mallophora ruficauda are ectoparasitoids of white grubs and adults are an important apiculture pest in Argentina. Females oviposit on tall grasses and the second instar larva actively searches and locates hosts. There are nine potential hosts in the distribution area of this parasitoid and Cyclocephala signaticollis (Coleoptera: Scarabaeidae) is the most parasitized in the field. However, M. ruficauda has a certain degree of behavioural flexibility towards different host species, and not being a strict specialist. The conditions under which the parasitoid orientates and accepts different hosts’ species are unknown. We studied the host specificity of M. ruficauda towards three species of Cyclocephala genus and we determined whether this specificity depends on larval age. We also evaluated whether larva orientation towards Cyclocephala species changes with chemical cue concentration. We assessed host specificity measuring the orientation and acceptance behaviours towards kairomones extracts and live individuals of Cyclocephala species using M. ruficauda larvae of low and high life expectancy (i.e., young and aged second instar larvae). We observed that young larvae orientated only towards C. signaticollis chemical stimulus, whereas aged larvae orientated also towards C. modesta, and the same was observed with increasing stimuli's concentration. Both young and aged M. ruficauda larvae orientate towards live C. signaticollis and C. putrida species and rejected C. modesta. Also, we found that larvae accepted all Cyclocephala hosts. In conclusion, our results indicate that specificity in the laboratory, observed through host orientation and host acceptance behaviours, depends not only on the availability of host species, but also on the nature of the host's stimuli combined with parasitoid age.

Large larval populations of the scarabaeid beetle Heteronyx piceus Blanchard that occur under peanuts, but not maize, in the South Burnett region of Australia are the result of a high rate and prolonged period of egg production by females feeding on peanut foliage. Heteronyx piceus is a relatively sedentary species and movement of females between adjacent fields is low. Populations of H. piceus varied markedly with landscape position. High larval populations are more likely (1 in 4 chance) to be encountered on the ‘scrub’ soils in the upper parts of the landscape than in the ‘forest’ soils in the lower half (1 in 20 chance), indicating that soil type/landscape position is a key risk factor in assessing the need for management intervention. The studies indicate that, because of the species' sedentary nature, the most meaningful population entity for management of H. piceus is the individual field, rather than the whole-farm or the region. The implications of this population ecology for management of the pest are discussed in relation to control strategies.

The development of Onitis caffer Boheman in cattle dung was studied in the laboratory. The larvae feed on the dung in which the eggs are laid. Egg to adult development at 25°C was completed in 24·7 weeks by a strain from a winter rainfall (WR) area of South Africa and 29·4 weeks by a strain from a summer rainfall (SR) area, and occurred without diapause. Maximum larval dry weight was achieved mid-way through the third larval instar, after which the larva emptied much of its gut to form a protective faecal shell, in which pupation occurred. At 20°C, 20% of WR larvae developed without diapause and the adults emerged after 33·5 weeks, whereas the remaining 80% of adults emerged after 80·1 weeks. In the SR strain, 70% emerged after 37·1 weeks without having entered diapause, while the remaining 30% emerged after 83·8 weeks. Thus, the period of diapause for both strains was 47 weeks and occurred in the third larval instar. At 15°C, 74% of WR larvae had pupated by 153 weeks, with a mean development time of 121·8 weeks. Zero development temperatures were 10·4°C (WR) and 10·1°C (SR), and day-degree requirements for development without diapause at 20°C were 2251 (WR) and 2571 (SR).

Experiments were undertaken in July and August 1982 in Northern Ireland to examine the effects of some factors which could influence the number of craneflies caught by water traps. Tipula paludosa Mg. and T. oleracea L. were caught, but the latter only in small numbers. Catches of males of T. paludosa, but not of females, decreased as the height of the trap walls increased. All catches were larger in traps of greater diameter. A significant colour preference was found for males of T. paludosa, in the order green > red > yellow > white > blue > black. Increasing the number of traps per unit area increased the mean catch per trap. It is concluded that the attraction of traps for craneflies, if any, is only slight and that the insects may descend randomly over traps so that greater numbers are caught in wide, low-walled traps. Catch is possibly greatest in green traps because of an inability of craneflies to distinguish them from grass.

In a country-wide survey of Culicoides in Nigeria 31 species were caught in light-traps set on the eaves of livestock pens. Three species, namely C. imicola Kieff., C. schultzei (End.) and C. milnei Aust., were most numerous and were found in all parts of the country. C. austeni C., I. & M. was predominant in mangrove swamps, C. schultzei in the hot Sudan zone and C. milnei was dominant on the plateaux. C. imicola and C. milnei were predominant in the forest zone while C. schultzei and C. imicola were dominant in the savanna zones. C. quinquelineatus Goetgh. was a southern species and was replaced in the north by C. moreli Clastrier. Peak catches of most species were between 01.00 and 05.00 h and a large proportion of the Culicoides were engorged with blood. The presence of large numbers of engorged Culicoides, especially C. imicola and C. milnei, around livestock indicates the danger of bluetongue virus transmission.

Oribius species are small flightless weevils endemic to the island of New Guinea and far northern Cape York, Australia. The adults feed externally on leaves, developing fruit and green bark, but their impact as pests and general host use patterns are poorly known. Working in Eastern Highlands Province, Papua New Guinea, we carried out structured host use surveys, farmer surveys, shade-house growth trials and on-farm and on-station impact trials to: (i) estimate the host range of the local Oribius species; (ii) understand adult daily activity patterns; (iii) elucidate feeding habits of the soil dwelling larvae; and (iv) quantify the impacts of adult feeding damage. Oribius inimicus and O. destructor accounted for nearly all the Oribius species encountered locally, of these two O. inimicus was the most abundant. Weevils were collected from 31 of 33 plants surveyed in the Aiyura Valley, and a combination of farmer interviews and literature records provided evidence for the beetles being pestiferous on 43 crops currently or previously grown in the Highlands. Adult weevils had a distinct diurnal pattern of being in the upper plant canopy early in the morning and, to a lesser extent, again late in the afternoon. For the remainder of the day, beetles resided within the canopy, or possibly off the plant. Movement of adults between plants appeared frequent. Pot trials confirmed the larvae are root feeders. Quantified impact studies showed that the weevils are damaging to a range of vegetable and orchard crops (broccoli, capsicum, celery, French bean, Irish potato, lettuce, orange and strawberry), causing average yield losses of around 30–40%, but up to 100% on citrus. Oribius weevils pose a significant and, apparently, growing problem for Highland's agriculture.

The larval populations of Busscola fusca (Fuller), a major pest of the guineacorn (Sorghum vulgare) crop, which survive the dry season in and around villages near the Research Station, Samaru, Northern Nigeria, were assessed by sampling. The larvae of B. fusca survive the five to six rainless months in diapause in crop residues, most important of which are guineacorn stems, which are stacked in the fields after harvest. Between 1956 and 1962, 100-stem random samples were collected from as many stacks as possible within an area of about six square miles. Each of the 348 samples was dissected immediately after collection and the number of living larvae of B. fusca per sample was recorded. The mean number of larvae per sample varied annually and ranged from 7 in the 1960–61 dry season to 33 in the 1959–60 dry season. The mortality of larvae is comparatively low between January and March, when most samples were collected, and it is concluded that the date of sampling did not unduly influence the estimates of annual variations of the population. The location of sampling areas also had surprisingly little effect and, despite uneven growth of the crop, the estimates of larval populations were remarkably uniform throughout the ten sampling areas and between samples within the main sampling area of Bomo village.

It is concluded that there is considerable variation in dry-season populations from year to year. The factors causing this variation have not been determined, and it is suggested that other workers might profitably continue and expand these investigations.

In recent decades, the oriental armyworm, Mythimna separata (Walker), has caused severe damage to staple grains in China. However, little is known about when M. separata begin their first migration and the role of males in reproduction and migration. Here, the migratory benefits and reproductive costs of flight frequency were examined in adults under laboratory conditions. We found that flying males had a positive effect on ovarian and reproductive development in females who flew for 1–2 nights by comparing two treatment groups (flying and nonflying male groups). Moreover, flying males decreased the flight capacity and flight propensity of females. In contrast, flight for more than two nights by males significantly inhibited ovarian and reproductive development in adult females. Compared with the controls (0 night), male flight for 1–2 nights significantly shortened the preoviposition period but significantly increased ovarian and reproductive development in females. However, male flight for more than three nights significantly inhibited female reproduction and flight capacity. These results indicate that M. separata begin their first migration within 2 days after emergence and fly for two nights. Prolonged flight times can result in significant reproductive costs. Females initiated their first migration earlier than males due to a stronger flight capacity. These observed findings will be useful for forecasting and monitoring population dynamics to prevent outbreaks of M. separata and reduce crop losses.

The question to which we have tried to find an answer is why malaria is almost absent in the southern region (II) within our field of observation, whereas it is endemic in the northern (I). We found Anopheles slightly less frequent in the former, but the difference is irrelevant, and the density of the Anopheline population in Region II is considerable, compared with almost all the European malarious countries we visited and where A. maculipennis is the local vector.

If this difference in the incidence of malaria is at all caused by a difference of the Anopheline faunas of the two regions (which need not be the case), then the biological distinctions are the only important ones. Morphological differences cannot interest us unless they are correlated with the former. Still we began by studying the latter, because they are easier to observe and to measure.