Based on the fact that in haematophagous Diptera, the basal bodies, groups of six to nine specialized epithelial cells in the calyx wall within the ovariolar sheath, become granular after ovulation, a method for rapidly determining parity of the females has been developed. After supravitally staining intact ovaries with fresh neutral red solution in physiological saline (1:3000–1:5000) for one to three minutes, granular basal bodies in parous females can be clearly recognized under a stereo-microscope or a compound microscope with a raised condensor. The advantages of the method are its speed, accuracy and simplicity.

The feeding rate of nymphs of Paulinia acuminata (Deg.) on Salvinia molesta was studied in the laboratory using single nymphs on different numbers of Salvinia leaves. Each successive instar ate more plant tissue, but at population densities likely to occur in nature it was unlikely that consumption rate could match the natural Salvinia growth rate. The controlling effect of Paulinia on Salvinia in Lake Kariba, Rhodesia, may therefore be negligible.

When studying the bionomics of certain species of the Ceratopogoninae in the Gold Coast, samples of material collected from different sources, where it seemed likely that the early stages of these small insects might be passed, were brought to the laboratory for examination. The samples were chiefly taken from rot-holes in live trees, from cut bamboo stumps, from decaying logs, from old canoes, from the edges of pools and puddles, from crab-holes, and from the bases of banana plants.

Field studies of orientation responses of the IIS-10.11 sibling of Simulium arcticum Malloch species complex and other simuliid species to host-mimicking cattle silhouette traps (CSTs) were carried out in the Athabasca region of Alberta, Canada. Simuliids were attracted to CSTs from downwind by a CO2 bait but very few were attracted to an unbaited CST. Passively searching simuliids tended to fly at lower levels than actively host seeking ones. Simuliids appeared to fly at lower levels when within visual range of the CST than when outside of it. Higher flight levels may improve chances of eventually making visual contact with the host or CST. Experiments in which a CO2 outlet was separated by increasing distances from a CST indicated that simuliids see the 1.1 m long CST at a range of approximately 8 m. Simuliids landing on the CST, whether CO2-baited or not, showed a strong preference for the trap's ends followed by the downwind side, followed by the upwind side. Species composition of collections from CST collections differed significantly from the species composition of cattle sweeps taken at the same times. Simulium vittatum was over-represented in collector catches in comparison to cattle sweeps. This bias may be due to species-specific differences in responses after landing on the CST since sweeps taken around CSTs had compositions similar to cattle sweeps. Results are discussed in terms of host orientation in biting flies in general and the suitability of CST-type traps as components of attractant-based control strategies and in simuliid population monitoring.

Based on a longitudinal survey performed in 1982–1983, a vector control strategy was implemented from 1985 onwards in a malarial-dense area of Burundi. One annual round of indoor spraying with malathion greatly reduced both the parasite load and the parasite rate in the population until 1989. However, from 1990 to 1993, a progressive resurgence of malaria was observed in most villages. For the present study, two villages were selected on the basis of their differential response to house spraying. In the village of Mulira surrounded by rice fields, the excellent results observed in the past have been followed by recent increases in parasite rates. In the village of Murengeza, also located in the rice growing area but near a river, the spraying had less impact. The inoculation rate was found to be similar in both villages, but the transmission peak occurred at the end of April in Mulira, and two months earlier in Murengeza. Indoor spraying with lambdacyhalothrin was carried out on 26 April 1993, one month too late according to the strategy intended. As no sporozoite mosquitoes were observed during the six months following spraying, this strategy should be maintained but, in villages near rivers, the application should commence much earlier, in mid-January. Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) and A. funestus Giles were found to be very endophilic species, whereas the dominant A. arabiensis. Patton was highly exophilic. Therefore it is recommended that treatments should not only be applied to human dwellings but also to other structures such as animal sheds, kitchens, etc, shown by earlier studies to be resting sites of A. arabiensis. This study underlines the need for regular reassessment in vector control programmes.

The different stages of Hindola striata Maa in Java and H. fulva Baker on clove (Syzygium) in Sumatra were investigated. Data are presented on the duration of egg and nymphal stages and their positions on the plant. Hymenopterous and Dipterous parasites attacking the eggs and nymphs are described. The natural enemy complex of these clove-dwelling insects is contrasted with that of H. viridicans Stål on Melastoma sp. Some observations on adult behaviour and biology are made, particularly as these relate to the spread of Sumatra disease.

The larvae of the Melolonthid beetle, Lachnosterna. consanguinea (Blanch.), have been found to be very destructive to sugarcane in the Dalmianagar area in Bihar, India, since 1956 when they were first recorded there. The pest has since been found to occur in serious numbers in certain adjoining areas and also in Bihta in Patna district. Damage is done by the larvae by feeding on cane roots. Heavily infested cane clumps dry out completely and in severe infestations as much as 80 per cent, of the crop is lost. The infestation occurs only on light sandy soils; crops on clay soils are not affected. The February-planted crop suffers more seriously than that planted in October. The adults have not so far been observed doing any damage to sugarcane.

The emergence of adults starts in the last week of April, but a rush of emergence occurs only after the first shower of rain. The adults are nocturnal in habit and feed on leaves of certain bushes and trees during the night. They hide themselves in loose moist soil in day-time. Mating takes place after dusk during the flight season, and eggs are laid in the soil at a depth of 5 to 10 cm. The incubation period varies from 8 to 10 days. The young larvae move to cane roots after some initial feeding on grass roots. They are fully grown in 8 to 10 weeks' time when they move deeper into the soil and pupate in earthen cells at a depth of 0·3 to 1·5 m. The pupal period varies from 12 to 16 days and the pest overwinters in the adult stage. There is only one brood a year.

The adults are active at night and are attracted to artificial light and can be destroyed in large numbers with the help of light-traps. Collections from the foliage of trees and shrubs at night is an easier and better method of destruction. Trials with insecticides applied as sprays to the foliage of shrubs in cages to which adults were immediately introduced showed that a suspension containing 0·5 per cent. DDT was effective and was superior to one of BHC.

Replicated field trials carried out for the control of the larvae with various insecticides showed that BHG applied to the soil in a dust at the rate of 22·4 Ib. toxicant per acre was the most effective. This treatment, when applied-at planting time (February) had an adverse effect on germination; this effect was not observed when the application was made at the end of May. In subsequent replicated experiments, when BHC in a dust was applied in two instalments at the rate of 10 Ib. per acre at the end of May at the time of the rush of adult emergence, and in July, respectively, much better results were obtained without any adverse effect on the crop. BHC and other insecticides applied to the soil in sprays at 10 Ib. per acre at the end of May were ineffective.

Amongst varieties of cane grown at the Bank Farm, Dalmianagar, Co.935 and B.O.3 showed a greater tolerance of injury by the larvae than the others.

A Scoliid, Scolia aureipennis Lep., was observed to parasitise the grubs during September. The rate of parasitisation was only about 5 per cent.

A disease caused by a fungus, Metarrhizium. anisopliae, was also observed to occur in the adults. Affected beetles died within 4 to 6 days.

The common Indian toad (Bufo melanostictus) and the gecko (Gecko gecko) were seen preying on the adults in the evening when these were active. A number of birds, particularly the Indian crow (Corvus splendens) and mynah (Acridotheres tristis), also feed on the larvae when these are exposed during tillage operations.

Baris granulipennis (Tourn.), originally described from Egypt, has become a serious pest of water-melons (Colocynthis citrullus) in Israel, where hitherto its presence has not been recorded, and has been found on melons and cucumbers, but not on vegetable marrow or squash. Economically serious damage results from girdling of the stem end of the fruit by the female, prior to oviposition.

The incubation period of the egg, on average, is 3·7 days at 30° and 6 days at 22°C. The larvae feed on developing seeds inside the fruit and pupate there. The total development period occupied from 25 to 42 days in the summer, when the temperature fluctuated between 24 and 29°C. The cocoon is made by glueing minute pellets together. These consist of dried pulp from the fruit mixed with a secretion which is ‘milked’ from the anus, and is believed to be produced in the Malpighian tubules. The preoviposition period is about four days, and the length of adult life is several weeks. There are three generations a year, and four if weather permits. Adults overwinter in hibernation. It is suggested that the increase of cucurbit cultivation, and the lengthening, by irrigation, of the cropping period, may have permitted an increase in the weevil population to pest proportions.

The effect upon the three-dimensional dispersion of experimental populations of Tribolium castaneum (Hbst.) of internal pockets of grain at 18 per cent, moisture content, either mouldy or free from mould, and superficial ones of 25 per cent, moisture content, in a larger bulk of 14 per cent, moisture content, was investigated at 25°C. The behaviour under these circumstances of insects reared and maintained at 70 per cent, relative humidity was compared with those conditioned at 40 per cent. R.H. for 14 days. It was found that insects reared at 70 per cent. E.H. did not accumulate in the damp grain whereas conditioned ones did. The underlying response was shown to be hygrokinetic and the mechanism an orthokinetic one. The rate of movement of unconditioned adults in grain of 18 per cent, moisture content was approximately twice that in grain of 14 per cent, moisture content. Conditioned adults moved very slowly in the damper grain. There were no significant variations in irregularity of pathway (klinokinesis) under any of these circumstances. When grain of 18 per cent, moisture content supporting a mould growth was used, unconditioned adults did, however, accumulate in it due to trophic behaviour.

While there is considerable plasticity of behaviour in this species a synthesis is attempted of the causal behavioural mechanisms underlying the spatial structure of populations in ecological situations involving humidity gradients; the results are also discussed in relation to grain storage conditions, and the detection and control of the species.

All varieties of sweet corn, in the seedling stage, are susceptible to frit fly attacks in England.

Different open-pollinated, hybrid and inbred varieties differ in susceptibility to damage by frit, indicating a possible genetical basis for resistance. Some breeders have produced less susceptible types than others.

Susceptibility is not associated with adaptability or maturity (i.e., comparative earliness when whole rows were ready for picking) of varieties but there is indication that seed origin is of some importance.

Sowing sweet corn at different dates influences the severity of attack. Peaks vary according to variety and year but generally sowings late in May are preferable.

Distribution of attack on a crop is at random, although there is a suggestion that plants in stringers from a central mass are mere damaged in the direction of the prevailing wind but there is no regular decrease in incidence with distance from the central mass.

Methods of tackling the frit fly problem include growing sweet corn in frit free areas, timing sowing dates, using prophylactic measures and breeding more resistant strains on genetical principles.

Descriptions are given of the tomato erineum mite, Aceria lycopersici, and the tomato russet mite, Vasates lycopersici, in Morocco, from which country the latter species is recorded for the first time.

A. cladophthirus is shown to be a synonym of A. lycopersici.

These two mites are almost world-wide in distribution and probably occur in most countries where tomatos are grown, but A. lycopersici has not been recorded from Australia or New Zealand.

1. Eight Ichneumonoidea, fourteen Chalcidoidea and six Proctotrupoidea are recorded as parasites of willow insects.

2. The majority of records are of parasites bred from insects inhabiting the wood of the cricket bat willow, Salix alba var. caerulea, Smith, the more important being Torymus pulchellus, Thoms., Tridymus salicis, Nees, Eupelmus urozonus, Dalm., Microterys clavellatus, Dalm., Tetrastichus roesellae, DeG., Tetrastichus inunctus, Nees, Tetrastichus flavovarius, Nees, Tetrastichus ? acuminatus, Ratz., and Platygaster sp.

3. Microterys clavellatus is recorded for the first time as a parasite of Cecidomyiidae.

4. Evidence is given for the separation of the gall-midges, Rhabdophaga sp. and R. saliciperda, Duf., as distinct species based both on structural differences and on a study of their parasites, for the three parasites found most commonly attacking Rhabdophaga sp. were never bred from R. saliciperda, and the most common species parasitizing R. saliciperda was never obtained from Rhabdophaga sp.

5. It is confirmed that Eurytoma salicis, Thoms., supplements its animal diet with vegetable food.

6. The rate of parasitism of Euura atra, Jur., by Eurytoma salicis is given as 19·8 per cent., and that of Rhabdophaga sp. by Platygaster sp. as 40·5 per cent.

7. Histograms are given of Rhabdophaga sp. and its parasites, Torymus pulchellus, Thoms., Tetrastichus roesellae, DeG., and Platygaster sp., the emergence of Platygaster sp. coinciding approximately with that of its host.

1. The chief pests of cocoa and chocolate are the Pyralid moths, Ephestia elutella (cocoa moth), E. kühniella (Mediterranean flour moth), E. cautella (fig moth), and Plodia interpunctella (Indian meal moth).

2. Beans are infested before arrival at the factory, this infestation commencing on the plantation and increasing during the various stages of transit to the factory. The docks, in particular, may be the most important source of infestation owing to the fact that there fresh consignments may be brought into direct contact with much older consignments already heavily infested.

3. The steps recommended for factory use are:—

(a) General cleanliness in all parts of the factory, avoidance of dead spaces which offer opportunities for breeding and pupation, removal of all waste material, constant sweeping, frequent whitewashing and distempering, etc.

(b) Heat treatment of beans on arrival at the factory and subsequent storage where they will not be liable to re-infestation. The heat treatment to consist of subjection to a temperature of 60° C.–65° C. for a time dependent on quantity of beans.

(c) The use of traps in the factory in order to keep down the numbers of stray moths. Such traps may consist of vinegar and syrup.

(d) The protection of all finished goods by means of fine-mesh materials so far as possible.

4. No insect life survives either roasting or any stage of manufacture in which the chocolate is in a molten condition.

5. Although parasites exist which prey on the larvae of these moths, it is not considered that extermination by means of them would be practicable.

6. Fumigation of warehouses, especially at the docks, is under consideration by the Empire Marketing Board, and any recommendation they may make will probably be applicable to factories. At the present stage, however, it is premature to make suggestions.

Species interactions are often context-dependent, where outcomes require an understanding of influences among multiple biotic and abiotic factors. However, it remains unclear how abiotic factors such as temperature combine with important biotic factors such as density-dependent food limitation and predation to influence species interactions. Using a native grassland – grasshopper – wolf spider model food chain in tallgrass prairie, we conducted a manipulative field experiment to examine how predator–prey interactions respond to manipulations of temperature, grasshopper density, and food chain length. We find that grasshopper performance responses to temperature and predator treatments were density dependent. At high densities, grasshopper survival decreased with increased temperature when no spiders were present. When spiders were present, grasshopper survival was reduced, and this effect was strongest in the cooled treatment. In contrast, grasshopper survival did not vary significantly with spider presence or among temperature treatments at low grasshopper densities. Our results indicate that context-dependent species interactions are common and highlight the importance of understanding how and when key biotic and abiotic factors combine to influence species interactions.

A comparison is made of all the members of the genus Thomasiniana Strand at present known from Rosaceous host-plants, namely T. oculiperda (Rübs.), the Red Bud Borer; T. theobaldi Barnes, the Raspberry Cane Midge; T. crataegi Barnes, the Hawthorn Stem Midge and a hitherto undescribed species from wild blackberry. Although morphologically very similar, each can be readily distinguished in trials on host-plant preference. By this means it has also been shown that there are two strains, favouring apple and rose respectively, within the present species T. oculiperda. Other biological and some morphological evidence is given, supporting the above conclusions, and on this basis the midge from blackberry is put forward as a new species for which the names Thomasiniana fruticosi, sp. n. and “Blackberry Cane Midge” are proposed and a formal description given. The biological and economic status of each species or strain is discussed and a list of the known parasites given.

Percentage mortality by itself is not a good measure of the practical value of an insecticidal treatment. In a relatively simple case, such as the fumigation of stored products, the control value can be expressed in terms of the time required for the reduced population to return to its former level of density, provided the mode of increase of the population is known.

Assuming that increase is at a regular exponential rate, the control values of different mortality percentages can be compared in terms of the calculated recovery times; thus, each of the values in the series 99·6, 93·75, 75, 50 and 29 per cent. mortality is twice as good as the one that follows it. Such relationships can be deduced from the graph provided, which is essentially a curve of constant exponential growth, made linear by the use of the logarithmic scale.

The above comparisons do not depend on the value of the constant rate of increase. If the rate of increase varies, control values can still be compared so long as it is possible to calculate the relative times needed for recovery from different levels of density.

A summary is given of the results obtained from the collection of large numbers of the puparia of G. tachinoides and G. morsitans in the Gadau-Sherifuri area and the breeding of tsetse and parasites therefrom. Totals of 106,047 puparia of G. tachinoides and 17,346 of G. morsitans have been dealt with during the two breeding seasons of 1930–31. It is concluded that the Bombyliid, Thyridanthrax argentifrons, Aust., is in this area the only naturally occurring pupal parasite of Glossina of any importance. This fly has formed as much as 6 per cent. of total emergences from G. tachinoides puparia in the month of March, and 2 per cent. of total emergences from G. morsitans puparia for the month of April.

Following successful small-scale trials, an attempt was made, by aircraft application of insecticide, to eradicate Glossina morsitans Westw. and G. pallidipes Aust. from an isolated block of savannah woodland, approximately 11 sq. miles in extent, at Chungai in the Central Province of Tanganyika between July 1958 and January 1959. A single-engined aircraft, fitted with two belt-driven rotary-cage atomisers, was used to apply a 5 per cent, solution of γ BHC in power kerosene at a nominal dosage of 0·08 gal. per acre (0.04 lb. γ BHC per acre). Seven applications were made at approximately 28-day intervals, the time taken to complete an application varying from five to eight days. The operation failed to control the flies. Although each of the first two applications reduced the apparent density of G. morsitans by about 90 per cent, and that of G. pallidipes by a lesser, although still considerable, factor, later applications gave varying and often low mortalities, and the populations increased slowly for some time, the insecticide applications causing only temporary depressions in numbers. Numbers fell towards the end of the operation, but final reductions were only about 50 per cent, or less. Kills of female flies were low, and this undoubtedly led to the eventual failure.

The low volume-dosage, a drop spectrum that possibly contained too few droplets of the required size, meteorological conditions, and biological factors that apparently favoured the survival of female flies are suggested as contributory elements to the low mortalities.

Operational costs were considerably lower than in previous work.

Palmicultor palmarum (Ehrhorn), a species of pseudococcid found mainly on coconut in Micronesia and Hawaii, is recorded for the first time from the Bahamas. Planococcus lilacinus (Ckll.) is discussed from Guyana, the first record for the New World, and Pseudococcus microadonidum Beardsley is recorded from the Seychelles causing damage to coconut.

The Oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), is a major pest of tree fruits worldwide, and the diapausing larvae overwinter in cryptic habitats. Investigations of overwintering G. molesta were conducted in adjacent peach, pear and apple orchards in Northern China over three consecutive winters to determine the overwintering site and habitat preferences of the moth. Counts of overwintering larvae in the different orchards demonstrated that the late-maturing peach orchard (‘Shenzhou honey peach’) was the most preferred overwintering habitat with more than 90% of the collected larvae. Larvae were more abundant in host trees, and they very rarely overwintered in the soil. The overwintering site preferences on the host trees were significantly different; over 50% larvae were located in the tree trunks, and followed by main branches. Most of the G. molesta overwintered on the sunny side of the host trees at or below 60 cm from the ground; a few were cocooned on the shaded sides of the trees or greater than 60 cm from the ground. G. molesta began overwintering between August and October, mid- to late September was the peak period for entering winter diapause during 2011–2013 (77.78, 67.59 and 71.15%, respectively). Our findings improve understanding of the orchard habitat and overwintering site preferences of G. molesta and would be useful in the development of efficient forecasting and pest-management strategies for orchards during the winter and early spring.