The koinobiont parasitoid Halticoptera circulus (Walker) is a potential biological control agent of leafminers, but it has only rarely been collected from the invasive leafminer, Liriomyza trifolii (Burgess), in Japan. To understand why this is the case, parasitism and development of H. circulus in L. trifolii was compared with parasitism and development in two indigenous leafminer species, Liriomyza chinensis Kato and Chromatomyia horticola (Goureau). There was no significant difference in parasitism rates by H. circulus in the three leafminer species and the eggs and larvae successfully developed in L. chinensis and C. horticola. However, H. circulus failed to develop in L. trifolii, where developmental stages were encapsulated by host haemocytes. This parasitoid may be a good agent to control indigenous leafminers such as L. chinensis and C. horticola but is unlikely to be useful for the biological control of the invasive L. trifolii in Japan.

Two Napier millet (Pennisetum purpureum×P. glaucum) hybrids, namely PBN 83 and PBN 233 and one sorghum (Sorghum bicolor) variety, SL 44, were assessed for their potential role as a trap crop in the management of the stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) on maize. Oviposition preference and larval survival and development were determined for different test plants under laboratory and screen house conditions. Further, field dispersal of C. partellus larvae was assessed between Napier millet and maize crops. Results from no-choice and dual-choice tests indicated that Napier millet hybrids were preferred for oviposition over maize by C. partellus moths. Sorghum was, however, not preferred over maize in this respect. Napier millet hybrids were poor larval hosts, and a rapid decline in larval numbers was noticed within the first five days after hatching and virtually no larvae survived to pupation. Leaf area eaten by the borer larvae was significantly less on these hybrids than on maize or sorghum. Plant damage was more severe in maize and sorghum than Napier millet hybrids. No appreciable larval shift was noticed from Napier millet hybrids to the adjoining maize crop. The evaluated Napier millet hybrids, therefore, had potential for use as trap crop in C. partellus management. Sorghum, however, did not hold promise in this respect.

A southern population (S) from Xiushui County (29°1′N, 114°4′E) and a northern population (N) from Shenyang city (41°48′N, 123°23′E) of the cabbage beetle, Colaphellus bowringi vary greatly in their life-history traits, and may serve as an excellent model with which to study the inheritance of life-history traits. In the present study, we performed intraspecific hybridization using the two populations, comparing the key life-history traits (fecundity, development time, body weight, growth rate, and sexual size dimorphism (SDD)) between the two populations (S♀ × S♂ and N♀ × N♂) and their two hybrid populations (S♀ × N♂ and N♀ × S♂ populations) at 19, 22, 25, and 28°C. Our results showed that there were significant differences in life-history traits between the two parental populations, with the S population having a significantly higher fecundity, shorter larval development time, larger body weight, higher growth rate, and greater weight loss during metamorphosis than the N population at almost all temperatures. However, these life-history traits in the two hybrid populations were intermediate between those of their parents. The life-history traits in the S × N and N × S populations more closely resembled those of the maternal S population and N population, respectively, showing maternal effects. Weight loss for both sexes was highest in the S population, followed by the S × N, N × S, and N populations at all temperatures, suggesting that larger pupae lost more weight during metamorphosis. The changes in SSD with temperature were similar between the S and the S × N populations and between the N and the N × S populations, also suggesting a maternal effect. Overall, our results showed no drastic effect of hybridization on C. bowringi, being neither negative (hybrid inferiority) nor positive (heterosis). Rather, the phenotypes of hybrids were intermediate between the phenotypes of their parents.

The potato bug, Closterotomus norwegicus (Gmelin) (Hemiptera: Miridae) is an introduced pest of lucerne, white clover and lotus seed crops in New Zealand and a key pest of pistachios in California, USA. Efforts were made to identify potential biological control agents of C. norwegicus in Europe. A total of eight parasitoids, including six primary parasitoids from the genus Peristenus (Hymenoptera: Braconidae) and two hyperparasitoids from the genus Mesochorus (Hymenoptera: Ichneumonidae), were reared from C. norwegicus nymphs collected in various habitats in northern Germany. With a proportion of more than 85% of all C. norwegicus parasitoids, Peristenus closterotomae (Hymenoptera: Braconidae), a new species, was the most dominant parasitoid, whereas other parasitoid species only occurred sporadically. Peristenus closterotomae did not fit in the keys to any described species and is described as new to science. Parasitism caused by P. closterotomae was on average 24% (maximum 77%). To assess the host specificity of parasitoids associated with C. norwegicus, the parasitoid complexes of various Miridae occurring simultaneously with C. norwegicus were studied. Peristenus closterotomae was frequently reared from Calocoris affinis (Herrich-Schaeffer), and a few specimens were reared from Calocoris roseomaculatus (De Geer) and the meadow plant bug, Leptopterna dolobrata (Linnaeus) (all Hemiptera: Miridae). The remaining primary parasitoids associated with C. norwegicus were found to be dominant in hosts other than C. norwegicus. Whether nymphal parasitoids may potentially be used in a classical biological control initiative against the potato bug in countries where it is introduced and considered to be a pest is discussed.

British Guiana has not been invaded by migratory locusts since the year 1886, when, as far as it is possible to ascertain from the records of those bygone days, the same species of locust was implicated. Also, on the occasion of this previous attack, it seems very probable that a swarm first infested the North West and Pomeroon areas and, multiplying there, migrated further down the coast to Berbice.

The following paper is based upon material received by the British Museum (Natural History) since the publication of the author’s “Further Notes on the Tabanidae of Palestine”* All the specimens referred to, including the types of the two new species described in the following pages, have been presented to the National Collection by the Imperial Bureau of Entomology. With the exception of the type of the new Tabanus (see p. 428) and a few other specimens, all taken by Mr. O. Theodor, the entire series has been collected by Dr. P. A. Buxton, to whose contribution in the last number of this Bulletin† the reader is referred for important field-notes.

Goniozus antipodum Westw. is redescribed, and three species, G. jacintae sp. n., G. collessi sp. n. and G. mandibulatus sp. n., are described from the females, figured and keyed. All are from Australia, and G. jacintae and G. mandibulatus are parasites of the tortricid Epiphyas postvittana Wlk.

Catches of Glossina palpalis palpalis (R.-D.) and G. tachinoides Westw. at high and low densities with hand-nets, biconical traps and an electric back-pack trap in Nigeria indicate that both types of trap are inferior to hand catching for routine checks of G. palpalis and G. tachinoides populations. Hand catching is recommended as being most suitable for large-scale surveys, assessment of control following insecticide spraying and classical fly-rounds. The biconical trap is recommended for use in experiments of a limited size, monitoring of fly populations on livestock ranches and around Villages, and for capturing flies for dissection. The electric trap is recommended for use in sampling flies in areas of medium and high density and possibly for blood-meal identification. Some blood-meals of G. palpalis were identified.

Laboratory and field experiments were carried out to study the toxicity of 3:5 dinitro-ortho-cresol and its sodium salt to the honey bee.

The acid DNOC was shown to be a rapidly acting poison under a wide variety of conditions and its toxicity was not greatly affected by differences in temperature or humidity during or after treatment.

Although both the acid and salt were equally toxic as stomach poisons, considerable differences were observed between the two substances as aqueous sprays and dry films. The toxicity of the sodium salt as an aqueous spray was considerably influenced by the humidity of the environment after spraying; the higher the humidity the greater the kill.

The sodium salt was apparently non-toxic as a dry film and increasing the humidity of the environment had no effect until the saturation point was reached and the salt went into solution. At this point the salt was almost as rapid in action as the acid. The type of surface on which the film was deposited was also shown to affect the toxicity.

Experiments were carried out on the penetration of the two substances through beeswax and these confirmed that whilst the acid could penetrate the beeswax in all forms tested the salt would only penetrate in aqueous solution.

The parasitoid wasp Cephalonomia tarsalis (Ashmead) (Hymenoptera: Bethylidae) is commonly present in stored product facilities. While beneficial, it does not provide a high degree of biological pest control against its host, the saw-toothed beetle Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). A candidate explanation for poor host population suppression is that adult females interfere with each other's foraging and reproductive behavior. We used simple laboratory microcosms to evaluate such mutual interference in terms of its overall effects on offspring production. We varied the density of the hosts and also the spatial structure of the environment, via the extent of population sub-division and the provision of different substrates. Production of C. tarsalis offspring was positively influenced by host density and by the isolation of females. With incomplete sub-division within microcosms offspring production was, in contrast, low and even zero. The provision of corrugated paper as a substrate enhanced offspring production and partially mitigated the effects of mutual interference. We recommend simple improvements to mass rearing practice and identify promising areas for further behavioral and chemical studies towards a better understanding of the mechanisms of mutual interference.

Tomato leaf miner (TLM), Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most destructive tomato pests worldwide. We tested quantity and quality of tomato fruits after simultaneous use of two biological control agents, the predatory mirid bug Nesidiocoris tenuis (Reuter) and the egg parasitoid Trichogramma brassicae Bezdenko against TLM. We varied the timing of predator releases (before or after pest establishment) and the number of parasitoids released (ten or 30 females per week per m2). The highest number of fruits per cage, percentage of undamaged fruits, total yield weight, and undamaged yield weight were all obtained with predator-in-first treatments, with or without parasitoid releases. Furthermore, measures of fruit quality were also highest in predator-in-first treatments, including, highest percentage of water, greatest proportional fresh weight of carbohydrates, most lycopene, most β-carotene, most flavonoids, and highest total chlorophyll. Thus, our findings support a predator-in-first augmentation approach for management of TLM.

♂♀. Red; thorax dark red; orbits, vertex, ocellar tubercle, almost white; wing veins very dark; costal veins and stigma yellowish red, as are often the tibiae and tarsi; abdomen somewhat darker towards apex.

Railway trains running through tsetse-infested country between Mombasa and Nairobi in Kenya Colony carry G. longipennis, G. pcdlidipes and G. brevipalpis on to stock-farming areas beyond the natural limit of the fly belt, thus being largely responsible for outbreaks of animal trypanosomiasis and a reluctance on the part of European, Asian and African settlers to develop the land, affected by this form of fly dispersal, to its full capacity.

The country through which the trains travel is described together with an account of a survey of the fly distribution.

Tabulated figures are given of the monthly totals of tsetses collected from passenger and goods trains by teams of fly boys posted at Emali and Sultan Hamud railway stations about 17 and 25 miles respectively outside the fly belt towards Nairobi More than 24,000 flies were collected over a period of one year and many, not collected by the de-flying teams, were carried up-country even as far as Nairobi, 101 miles from the fly belt.

Tsetses were collected from inside passenger trains, but very much larger numberswere taken from the outer surfaces and undercarriages of goods trucks.

Reference is also made to the rôle of motor traffic, especially when in convoy in the dispersal of tsetses.

The incidence of animal trypanosomiasis along the line of the railway is dealt with and the association of the disease with tsetses carried by trains is supported by results of laboratory experiments on the transmissibility of Trypanosoma congolense, T. vivax and T. brucei by the three species of flies concerned.

Bush-clearing on stock farms outside the fly belt will not protect the cattle from infection carried by flies brought by trains but bush-clearing in specified localities of fly concentration in the infested country is recommended as a measure to reduce the numbers now attracted to trains. It is considered that the spraying of trains will bring considerable relief to farmers ; but, so far, no suitable spraying apparatus has been devised nor has a reasonably cheap insecticide been found for this purpose.

The importance of the reaction of mosquito breeding water was established by MacGregor in 1921, and since then observations have been reported from various parts of the world. In the original paper MacGregor showed that, in the laboratory, three species of English mosquitos could survive an alkalinity of pH 9·6 and died in acid water of pH 4·4, while two other species developed in pH 4·4. Later, in Mauritius, he found the local Anophelines in water ranging from pH 9·5 to pH 8·4 and rarely in places giving the reading pH 7·4 ; and maintained that the reaction of any water there was a reliable index of the presence of Anopheline larvae. Senior White, in Ceylon, found the local Anophelines in water with readings from pH 5·8 to pH 8·6 usually, and decided that on the whole the local Culicines had a more restricted range. Buxton, in Palestine, found six species of Anopheles in water varying from pH 9·2 to pH 7·4, and of these only one occurred in water less alkaline than pH 8. He notes that Nablus, where the water supply is unusually acid for Palestine (pH 7 to 7·5), is free from malaria.

A technique is described for maintaining colonies of mosquitos belonging to the genus Mansonia, subgenus Mansonioides, which have root-piercing larvae and pupae. The colonies are maintained in the absence of living plants. The females lay their eggs on discs of wet-strength crepe paper floating on the surface of water in small 10 × 6–cm. containers. Sheets of the same paper, 14 × 10 cm., stand vertically in the larval infusion bowls and the larvae attach themselves to, and pupate on, these sheets of paper, which contain air spaces. The papers are changed three times a week and this ensures an adequate air supply for the aquatic stages. The larval infusion is produced by soaking pellets of a proprietary animal-diet (Diet 18) in water, at the rate of 20 g. pellets per 1,500 cc. tap water, allowing to stand 3–7 days and using diluted 1:5 with water. The infusion in each larval bowl is stabilised by a block of turf, and yeast is added three times a week; this ensures a continuous supply of micro-organisms on which the larvae feed. The pupae are removed whilst still attached to the sheets of paper, these being transferred to covered bowls, containing tap water and a turf block, in which the adult mosquitos emerge. Pupal mortality is found to be about 40 per cent. With this technique, monthly production of adults has averaged about 2,000 and 1,300 in two insectaries, but has continued to fluctuate between wide limits. The fluctuations have not shown seasonal periodicity, but the numbers produced per month in the two insectaries are correlated significantly, although the insectaries are managed independently. This may reflect variations in the balance of micro-organisms in the standard nutrient infusions used, which could affect mortality amongst firstinstar larvae.

Effects of five weed management regimes on abundance of weeds, insect pests, generalist predators and on pest damage and rice yield were investigated in upland rice in Côte d‘Ivoire over two years. In both years there was a highly significant negative correlation between weed biomass and grain yield across all treatments. Only two pest insect groups, Nephotettix spp. (Cicadellidae) and seed sucking Heteroptera, were consistently more abundant in unweeded plots and had a consistent significant positive correlation between abundance and weed biomass across all seven treatments. These polyphagous groups may have been more dependent on resources provided by weeds than the other pests studied. However, pest damage was not affected by presence or absence of weeds, suggesting that populations were below a damage threshold. Ants were the most abundant predators in the rice canopy and were most abundant in unweeded treatments. Abundance of both ants and spiders was significantly positively correlated with weed biomass across treatments. Abundance of reduviid bugs was positively correlated with weed biomass only in 1995. Any benefits due to presence of weeds in the crop were completely outweighed by loss of crop yield due to weed competition. However, if crop losses due to weeds were sufficiently reduced, it is possible that significant losses due to insect pests might emerge.

The amidinohydrazone insecticide hydramethylnon, exhibited delayed toxicity to workers of Reticulitermes santonensis Feytaud and Microtermes lepidus Sjöstedt over a range of concentrations, with deaths starting two to six days after exposure. R. santonensis workers which had been exposed to hydramethylnon passed the insecticide to untreated termite workers, larvae and nymphs by trophallaxis. Laboratory colonies of R. santonensis exposed to hydramethylnon were killed completely within 20 days. The possible use of hydramethylnon impregnated baits for the control of subterranean termites is discussed.

An account is given of an attempt to estimate changes in the rate of egg laying in a warehouse and in an unheated outbuilding at the laboratory. Small samples of food were placed on pieces of newspaper on the floor, and were renewed regularly, weekly or fortnightly in the warehouse and daily at the laboratory. Larvae were bred from these food samples and counted.

The rate of oviposition was found to depend on temperature, especially in winter, and on relative humidity, especially in summer. It was seldom cold enough indoors, in unheated premises, to prevent oviposition entirely for more than a few days at a time, 5°C. being the approximate minimum temperature for oviposition. It was never so dry at the laboratory that egg laying stopped but this did happen at the warehouse in July, 1946. Free drinking water is necessary for continued oviposition and this was available from rain in both buildings.

Darkness causes an increase in activity and in oviposition and most of the eggs in the foods supplied were laid at night. Foods placed near the daytime hiding places of adults were most used for oviposition.

Myosoma nyanzaensis sp. n. is described and illustrated, and is distinguished from the only other known Old World species, M. chinensis (Szépligeti) comb. n. (= Bracon chinensis Szépligeti). M. nyanzaensis is the first species of the genus to be described from the Afrotropical Region, where it has been reared as a gregarious ectoparasitoid of larvae of the pyralid moth Chilo partellus (Swinhoe) infesting maize and sorghum.

Six species of Cryptolestes that occur in stored products (C. ferrugineus (Steph.), C. capensis (Waltl), G. pusillus (Schönh.), C. turcicus (Grouv.), C. pusilloides (Steel & Howe) and C. ugandae Steel & Howe) showed different susceptibilities to fumigation with methyl bromide at 30°C. and 80 per cent. relative humidity. The susceptibilities were partly correlated with morphological and bionomic differences between the species: C. ferrugineus was the least susceptible.