Field trials in 1958–62 at Gatooma Research Station, Rhodesia, in which carbaryl, DDT, endrin and endosulfan were compared for controlb of insect pests of cotton, confirmed earlier laboratory results which showed that larvae of Diparopsis castanea Hmps. were more susceptible to carbaryl than those Heliothis armigera (Hb.) but that the latter were more susceptible to DDT. Counts of larvel populations showed that neither insecticide used alone could control the bollworm complex statisfactorily. The results indicated that optimum control could best be achieved by applying one or other insecticide as appropriate after inspection of the crop to determine the level of insects attack at diffetent stages during the seasons, rather than by use of mixtures of both insecticides. It is recommended that dimethoate should be added to either of the insecticides for aphid and red spider mite control when required.

A species of Xyloryctid moth bred from larvae feeding on the leaves of tea (Camellia sinensis) in Hong Kong is described as new and is named Neospastis sinensis sp.n. The species is differentiated from the three other known representatives of the genus, and also from Synchalara rhombota (Meyr.), which is a pest of tea in India, and S. rhizograpta Meyr., which was originally described from China. Illustrations of both sexes of the adult and genitalia and of N. sinensis are given.

A method is described by which Homorocoryphus nitidulus vicinus (Wlk.) was reared in numbers continuously in the laboratory. This is believed to be the first account of the continuous labouratory culture of a Tettigoniid. Details are given of a substitute oviposition site that enables the eggs to be easily collected. The basic food used was grass, which was supplemented with cereals. The problem of cannibalism and methods of reducing it are discussed. Brief information on the bionomics of the crickets under these conditions is included.

The names of 156 Culicine mosquitos that are known to occur in Tanganyika are listed, together with a further three species of undetersting status. Systematic notes are included for species that show interesting taxonomic features, and locality records and the source of the information are given for each species. The distribution of the species in relation to zoogeographic and climatic regions if summarised in a table.

In tests of the reactions of freshly hatched larvae of Plodia interpunctella (Hb.) to droplets of liquids containing an insecticnde, 16 droplets of the test material were disposed in a ting 23 mm. in diameter on a glass surface. The mean diameter of dtoplets of the different oils used as solvents varied from about 330 to 615 μ. Minute glass beads about 680 μ in diameter were used as controls. The larvae were tested individually by placing them at the ecntre of the ring and noting whether ot not they succeeded in escaping from it without making contact with a droplet, and their time to do so, termed the avoiding-time.

Six petroleum hydrocarbon oils, and pyerthrin at different concentrations in one of them (Shell Risella Oil 17) and pyrethrin synergists, piperonyl butoxide and Bucarpolate (2-(2-n-butoxyethoxy)ethyl 3,4-methylenedioxybenzoate), were tested. Droplets containing 20 per cent. pyrethrins proved the most repellent, over 98 per cent. of the larvae avoiding contact with them, whereas only 47.5 per cent. avoided the glass beads. The degree of avoidance elicited by the oils was inversely related to the values of their physical characteristics, such as initial boiling point and mean molecular weight. Increasing concentrations of pyrethrins increased both the degree of avoidance and the avoidingtime, and the addition of piperonyl butoxide or Bucarpolate enhanced both these reactions.

Investigations of the feeding activity, resting behaviour and seasonal distribution of Glossina morsitans Westw. were carried out at Lusulu Veterinary Research Station, Rhodesia, in 1961–63. Nine principal sampling sites were used, one in each of five distinct vegetation types and four at places where various pairs of types met. At each site, from dawn to dusk on several consecutive days in each of four seasons, tsete flies that had engorged naturally on a tethered ox were caught, marked and released, and meterorological readings were taken. Daylight observations of resting flies, both marked and unmarked, were made by searching the vegetation from ground level to a height of 25 feet (with the aid of ladders) and also by placing nets over inaccessible resting places, such as ant-bear holes, at the hottest time of day, thus trapping the flies that emerged later. Attempts to determine the night resting places by releasing flies marked with reflecting paint were unsuccessful.

The results showed that the feeding activity of G. morsitans was restricted to temperatures between 18°C., below which the flies were inactive, and about 32°C., above which they echibited a negative reaction to light. Feeding ceased abrupthy with the onset of darkness, and these was some evidence that activity was reduced by very high light intensity during the middle hours of sunny days. The diurnal pattern of feeding activity varied considerable from season to season but relatively little between vegetation types. A sex ration near equality was observed amongst flies caught feeding on oxen. The proportion of marked flies recaptured (i.e., feeding a second time on a bait-ox) was low, ranging from 0 to 12 per cent. according to vegetation type and season: it was higher for males than for females.

During daylight, the boles and branches of trees were used as resting places in all vegetation types, branches (especially horizontal ones) being preferred at most seasons. When temperatures rose above 32°C., however, the flies removed to resting places in deep shade, e.g., ant-beat holes, rock crevices, tor holes in trees and the fluted boles of dark-barked trees. Searching at night with electric torches failed to reveal the resting places used at that time.

The catches of feeding flies indicated that a wide range of vegetation types at Lusulu were inhabited by G. morsitans at all seasons and that, with the exception of males in riverine vegetation in the hot dry season, vurtually no concentration of flies took place in any specific vegetation at any time of year. These findings are discussed in relation to control by discriminative clearing.

Fourth- and fifth-instar hoppers and adults of Locusta migratoria migratorioides (R. & F.) were expected to three fluctuating remperature regimes in Weyco climatic cabinets and weighed daily. The regimes were 30 ± 0.25, 30 ± 10 and 30 ± 15°C., the change from one extreme to the other in the last two being made every two hours. Temperatures were accurately determined, by plantinum-resistance thermometers whose dimensions approximated to those of adult locusts, and were automatically recorded. The three thermorhythms were analysed by methods based on Fourier’s theorem, whereby a given wave form can be described in terms of a basic sine weve and a series of superimposed harmonics.

The rates of growth (weight increase) in the 4th-instar and adult at 30 ± 10°C/ were higher than at 30 ± 0.25°C. and were within 10 per cent. of the means of the rates at constant temperatures of 20 and 40°C., whereas the frowth rate in the 5th instar, and the pre-copulation and pre-oviposition periods of adults and their rate of weight loss when starved, were the same under both regime. At 30 ± 15°C., 5th-instar hoppers did not survive and, in comparison with the other regimes, the growth rates of 4th-instar hoppers and adults were very much lower, the pre-copulation period of adults was the same but the pre-oviposition period was much longer and their rate of weight loss when starved was doubled. Adults locusts were also tested at 30 ± 17.5°C., but most of them died within 24 hours and all within three days.

An account is given of the history of chemical control Phthorimaea operculella (Zell.) in potato fields in Rhodesia since the introduction of DDt prior to 1952. The failure of DDT and endrin, in routine spraying, to control field infestations is reproted, and some evidence that this is due to insecticide resistance is given. The results of critical field trials made in 1961, 1964 and 1965 to evaluate a range of insecticides for control of P. operculella and for their effects on populations of Macrosiphum euphorbiae (Thos.) are presented, together with the results of some laboratory tests. Good control of P. operculella in the field was obtained with sprays of azinphos-methyl at the rate of 0.5 lb active ingredient in 20 gal. water per acre, and two new compounds, methidathion and chlorfenvinphos, showed promise for the future.

In a collection of larvae of Culcine mosquitos made in northern Iraq in 1952–56 during the course of a survey of potential Amopheline breeding places in the area, the folowing genera and species were represented: Uranoaenia unguiculata Edw., Aedes caspius (Pall.) Culiseta longiareolata (Macq.), C. subochrea (Edq.), Culex theileri Theo., C.tritaeniorhynchus Giles, C. pusillus Macq., C. hortensis Fic. and C. mimeticus Noé. The last two species are reported here for the first time from Iraq. The records of Culiseta suochrea and Culec pusillus are based on a single larva of each.

Following heavy infestations of garden pea (Pisum sativum) by leadmining insects at an experimental farm near Baghdad in 1963, collections of infested leaves from crop plants and associated weeds were made in 1963–1965 in central and souther Iraq and teh insects emerging from them identified. These included the following six pieces of Agromyzid flies: Phytomyza atricornis Mg., Liriomyza congesta (Beck.), L. Brassicae (Ril), L. strigata (Mg.,) Liriomyza sp. and Agromyza nana Mg. Of these, P. atricornis was the most abundant and widely distributed, followed by L. congesta.

P. atricornis was found on a wide range of hosts, of which P. sativum and Taraxacum monochlamydeum wwre those most attacked. Six species of Hymenopterous parasites were recorded from P. atricornis and these are listed.

Bathycoelia thalassina (H.-S.), of which the developmental stages and life history are described, is responsible for premature ripening of cocoa pods in Ghana. Experiments conducted at Tafo to determine the nature of the damage to pods showed that the insect feeds directly on the beans, and that beans so attacked turn brown and subsequently die: only the empty shell of the bean remains.

The saliva of the insect kills any tissue of the pod that it penetrates and within four days the injured areas cease to grow and become yellow, then brown, and finally black.

The symptom most characteristic of damage is the change in colour. The pod may become completely yellow, or yellow in the basal or distal half only (usually the latter) or yellow in spots, depending on the size of the pod, the site of attack, and the duration of feeding at each site.

The insect usually attacks pods of the Amazon varieties, 10–17 cm. long. The incision made by the stylets is microscopic, and is covered by a jelly-like substance, and no evident lesions develop on the surface as in damage caused by cocoa mirids or coreids.

Damage caused by B. thalassina on young pods resembles cherelle wilt of physiological origin, and the two can be distinguished only by slicing the pods, whereupon the former can be recognised by the presence of injured beans.

According to the survey of damage caused by B. thalassina in Ghana, this species seems to be an economic pest on some Amazon and hybrid types of cocoa, whereas Amelonado cocoa usually suffers little.

From obsevations on larvae from laboratory-reared females of Glossina morsitans orientalis Vanderplank, six stages were recognised between the time of deposition (signalled in these experiments by a simple automatic device) and completion of puparium formation, each characterised by an associated pattern of behaviour. They are termed crawling (during which there is a stron phot-negative response), circling and reversing, head retraction, barrelling (the assumption of the puparial shape), hardening, and darkening. In choice-chamber experiments, crawling larvae markedly preferred moist to dry air but showed no response to gravity. In daylight at 26°C., larvae introduced into translucent plastic tubing travelled up to 65 in. before pupating; under bettwe conditions for locomotion they would probably go further. The interval before pupation was longer the earlier in the day birth occurred and was greater in light (average 108 min.) than in darkness (average 40 min.) and least, perhaps because of the contact stimulation, in sand in darkness. When bodily contact was minimised by suspending larvae by a thread tied round or stuck to the polypneustic lobes, pupation was accelerated; this possible reflected the mechanical stimulation of the handling, for pinching the larva with forceps produced a similar acceleration.

A new species of thrips is described which is predatory on Tetranychid mites on apple trees in Iraq. It bears a superficial resemblance to species of Scolothrips, but in view of the undivided tarsi and the chaetotaxy of teh head and pronotum it is placed in a new genus as Parascolothrips priesneri sp.n.

The insecticidal Potencies of DDT, dieldrin, isobenzan, malathion, diazinon and arprocarb were assessed both by topical application of oil solutions to test insects any by exposing the latter to residues on glass, using young male and non-pregnant female adults of Glossina morsitans submorsitans Newst., G. austebi Newst., and Chrysomya putoria (Wied.).

By topical application, dieldrin and isobenzan were 10–23 times as potent as DDT, but their residues were on ly 2.2–6.3 times as effective; arprocarb was likewise more effective by topical application than as a residue, being, respectively, 9 and 3.5 times as effective as DDT. In contrast, diazinon, and, especially, malathion tended to be more efficient, relative to DDT, as residues than might be expected from application tests.

It is presumed that the difference between the ralative potency of an insecticide as a reesidue and as applied topically reflects the physical factors affecting contamination and penetration of the insect, but these matters have nor been stuided with tsetse flies.