In the course of investigations on sawflies of economic importance, Emphytus cinctus, L., and Blennocampa waldheimi, Gimm., have been found causing injury to Rosaceae.

The foraging behaviour of frequency-dependent prey selection by larval instars of Toxorhynchites splendens (Wiedemann) was studied in the laboratory. Prey size selection (second vs fourth instars of Aedes aegypti Linnaeus or Anopheles stephensi Liston) by third and fourth instar predators was frequency-dependent. However, in the case of second instar predators, prey size selection was not frequency-dependent and the predator preferred second instar to fourth instar prey. When offered second instars of Aedes aegypti and Anopheles stephensi the preference for one species over the other was frequency-dependent in all the three predator instars. The role of frequency-dependent prey selection in the stability of prey—predator interaction at low equilibrium levels is discussed.

Illustrated descriptions of galls, larvae, pupae and adults, with a diagnostic key, are given for five species of Psectrosema Kieffer (= Amblardiella Kieffer = Isosandalum Kieffer) collected from various species of Tamarix during field surveys of potential biocontrol agents undertaken by the Commonwealth Institute of Biological Control in Pakistan. The genus Psectrosema is re-defined and the eleven species previously described from Europe, North Africa, India and Kazakhastan, USSR, are listed, mostly as new combinations. The five species recorded from Pakistan are P. manü nom. nov., stat. rev., comb. n. (= tamaricis Mani) from T. dioica; P. indicum sp.n. from T. indica; P. reticulatum sp.n. from T. hispida, T. androssowii and T. arceuthoides; P. unicornis sp.n. from T. dioica; and P. parvum sp.n. from T. indica.

The larval survival and development times of Aedes caspius (Diptera: Culicidae) were examined in the laboratory. These life history traits were estimated using life tables constructed for two populations, one of which had been subjected to a long-term larvicide control program. Traits were evaluated for eight different population densities. The effects of population, larval stage and larval density were investigated using a general linear model. Density was positively correlated with larval survival but did not affect development time. The fourth instar and pupae had the lowest larval survival rates. First and fourth instar larvae had the longest development times. These traits were not significantly different between the two populations. The effect of larvicide control on these traits is discussed.

Results are presented of 15 experiments made in north coastal districts of New South Wales from 1957 to 1961 with insecticides against the weevils Amnemus quadrituberculatus (Boh.) and A. superciliaris (Pasc.), the larvae of which have been reported as pests attacking the roots of clover (Trifolium repents, T. pratense and T. subterraneum) there. The adults live above ground, and single surface applications of insecticides were made to pastures in the form of dusts, granules or dilutions of emulsifiable concentrates in January, when maximum numbers of weevils were present and before significant oviposition had taken place. Insecticidal control was assessed by soil sampling for larvae in July–August, during the following winter. Pasture cuts were made in an attempt to assess the effect of treatments on the yield of clover.

Dieldrin at rates of 2 and 4 lb. per acre gave near eradication of Amnemus for one year, and satisfactory control was obtained with 1 lb. per acre. Aldrin, endosulfan (Thiodan) and BHC were less effective, and limited tests with heptachlor suggested that it was inferior to dieldrin. The scanty results available suggest that dieldrin is effective against Amnemus for only one year, but it is doubtful if annual applications are warranted. Owing to the patchy distribution of clover in the pastures, only one experiment showed an increased yield of clover associated with the reduction in numbers of larvae of Amnemus brought about by the application of 1 lb. dieldrin per acre. Similarly, poor persistence of clover on all plots prevented assessment of any residual effect on yield in the second year.

No method was found by which accurate estimates could be made of the density and distribution of adults of Amnemus in pastures to which insecticides were to be applied. Treatments, therefore, were replicated more frequently than was needed statistically in order to ensure that measurable levels of larval infestation were present at sufficient sites.

Small plots (500–700 sq. ft.) proved of little value, and this is attributed not only to contamination of control plots but possibly also to the death of weevils that moved from untreated into treated plots. Large plots (13,000–21,000 sq. ft.) gave the most consistent results in assessment of insecticides.

Control of Amnemus did not increase the productivity or persistence of clover, and it is concluded that any benefits from control are unlikely to be significant unless other factors, such as competition from grasses, drought, floods, nematodes and diseases of clover, which affected the density and persistence of clover in these experiments, are not limiting.

Adult female reddish or brownish ochreous with a dark marginal zone, to uniform dark castaneous. Broadly oval to sub circular; flat; margin evenly rounded, without trace of stigmatic clefts (fig. 1, a). Anal cleft completely fused, its position marked by a slight ridge and thickening of the derm. Anal operculum approximately central, the distance from posterior margin of body to anterior extremity of operculum being equivalent to nine-twentieths of the total length. Valves of operculum (fig. 1, d) elongate; basal edge nearly twice as long as outer edge; inner edge more than twice the length of the outer edge. Antenna (fig. 1, c) 7-jointed: formula, 3,7, (2, 4), 5, 6, or (3, 4, 7), 2, 5, 6. In some examples there are traces of a division in the third joint.

In a previous paper (Ann. Applied Biol. i, 1914, pp. 41–76) in which the author dealt with the life-history of Pegomyia hyoscyami, Panz., it was shown that the foodplants of this species belonged principally to the natural orders Chenopodiaceae and Solanaceae. Various weeds have also been cited in this connection, namely, certain kinds of thistle and the dandelion. Recently E. M. Vassiliev (see Rev. Appl. Ent. iii, Ser. A., 1915, p. 608) has added to the record the following:—Silene (catchfly), Datura stramonium (thorn-apple) and Onopordon acanthium (Scotch thistle). Thus, in addition to the two aforementioned, the orders Caryophyllaceae and Compositae are fairly well represented. As the original paper of the Russian author is not available, it cannot be definitely stated in how far his records are authentic. But as he advises the removal of these weeds from the vicinity of beet plantations, one would naturally infer that he has some reason for assuming that they may be attacked by the mangold fly and presumably provide an ever-present source of infestation to the cultivated crop.

The Capsid described in the present paper came under observation in Malaya some years ago but was not then specifically determined. Mr. W. E. China, of the British Museum (Natural History), was kind enough recently to examine it, and came to the conclusion that a new genus should be erected to contain it. Specimens were returned to me by Sir Guy Marshall, Director of the Imperial Institute of Entomology, along with some notes made by Mr. China which would be of use in the preparation of the diagnosis of the new genus.

The following investigation of the development of Laccifer lacca, Kerr, was carried out in the Department of Zoology, Lucknow University, under the supervision of Professor K. N. Bahl, D.Sc, D.Ph., to whom I am much indebted for the extensive facilities enjoyed in his laboratory.

A method is described for rearing Drosophila melanogaster Mg., which provides a high and consistent yield of adult flies, of uniform age and size, for insecticide studies.

Very small, shining black, evenly, but rather sparsely covered with very regular, equally long, pale, short, depressed hairs.

Head very strongly deflexed, including the eyes more than three times as broad as long, seen from above, but actually only a little more than one and a third times as broad as long seen in full face ; seen from the side (fig. 2, a) shorter than height at base ; frons and vertex moderately convexly arched, the vertex between the eyes about twice as wide as the diameter of one of the eyes (which are feebly prominent) ; basal margin of vertex between the eyes distinctly carinate, and slightly overlapping the anterior margin of pronotum ; clypeus flat, not at all prominent, and obscurely delimited from the frons ; rostrum extending to the hind coxae, the basal joint incrassate and reaching the base of the front coxae ; antennae moderately short, inserted close to the front margin of the eyes at about two-thirds of the distance from the base of the eye to its anterior apex, first joint slightly incrassate, cylindrical, extending to the apex of the clypeus, second joint incrassate more or less fusiform, the apex much thicker than the base, about three and a half times as long as the first joint, the third and fourth sub-equal, slightly thinner than, and about twice as long as, the first joint.

Representatives of three species of sawfiies attacking guava (Psidium guajava, L.)in Brazil, were recently sent for determination by Dr. Louis Pyenson, formerly head of the Entomology Section of the Instituta de Pesquisas Agronomicas, Pernambuco, Brazil.

In view of the possible danger of the introduction of yellow fever into the Far East the Government of Hong Kong has instituted a very thorough investigation of the mosquitos occurring in the Colony, and the Governor has recently forwarded to the Colonial Office an interim report by Dr. Harold Macfarlane, the Government Bacteriologist, to whom the work has been entrusted.

Information on longevity and on the effect of ageing on pheromone signalling in Bostrichidae infesting stored products is important because pheromones play a crucial role in mediating aggregation by the species in storages. The longevity of starved and unstarved Prostephanus truncatus (Horn) and Rhyzopertha dominica (Fabricius) were determined at 28±1°C, 65±2% RH and L12:D12 cycle. Additionally, the effects of ageing on rate of pheromone emission were investigated in R. dominica by comparing emission rates of the aggregation pheromones Dominicalure-1 (DL1) and Dominicalure-2 (DL2) released by adult males ranging from 4, 8, 12, 24 and 48 weeks of age. Mean survival time of starved male and female P. truncatus was 8.6±0.6 and 9.1±0.4 days, respectively. Starved R. dominica males lived for 5.7±0.2 days, and females for 4.7±0.1 days. However, mean survival times were not significantly different for starved males vs. females of either species. Mean survival time of unstarved male and female P. truncatus was 27.5±2.0 and 18.0±3.3 weeks, respectively, and for unstarved male and female R. dominica was 26.1±2.8 and 16.7±2.9 weeks, respectively. Difference in mean survival times of unstarved males vs. females in both P. truncatus and R. dominica were significant. Between species, no significant difference was observed in mean survival time between unstarved males of P. truncatus or R. dominica, nor between females of both species. Rate of pheromone emission in R. dominica was higher when the insects were relatively young (4, 8 and 12 weeks old), but declined by almost 55% in treatments where the insect were at about 24 or 48 weeks old, suggesting that recruitment potential of R. dominica might reduce substantially as the insects age.

The tomato Mi-1 gene mediates plant resistance to whitefly Bemisia tabaci, nematodes, and aphids. Other genes are also required for this resistance, and a model of interaction between the proteins encoded by these genes was proposed. Microarray analyses were used previously to identify genes involved in plant resistance to pests or pathogens, but scarcely in resistance to insects. In the present work, the GeneChip™ Tomato Genome Array (Affymetrix®) was used to compare the transcriptional profiles of Motelle (bearing Mi-1) and Moneymaker (lacking Mi-1) cultivars, both before and after B. tabaci infestation. Ten transcripts were expressed at least twofold in uninfested Motelle than in Moneymaker, while other eight were expressed half or less. After whitefly infestation, differences between cultivars increased to 14 transcripts expressed more in Motelle than in Moneymaker and 14 transcripts less expressed. Half of these transcripts showed no differential expression before infestation. These results show the baseline differences in the tomato transcriptomic profile associated with the presence or absence of the Mi-1 gene and provide us with valuable information on candidate genes to intervene in either compatible or incompatible tomato–whitefly interactions.

The chalcid, Oomyzus sokolowskii Kurdjumov has been recorded in many parts of the world as a major larval–pupal, gregarious endoparasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. This study investigated intraspecific variation between two populations of O. sokiolowskii, one from Cape Verde Islands, West Africa and the other from Hangzhou, China. In all crosses and backcrosses between the two geographical populations, the numbers of progeny and sex ratio of progeny were similar to those obtained within each of the populations, demonstrating complete reproductive compatibility between the two populations. The two populations showed similar responses to temperature with respect to development time and survival of immature stages. Observations on the interactions between the two O. sokolowskii populations and Cotesia plutellae (Kurdjumov), another major parasitoid of P. xylostella, showed that neither population could achieve successful parasitism of P. xylostella larvae already parasitized by C. plutellae. However, both O. sokolowskii populations could achieve hyperparasitism by ovipositing into a mid-late stage larva of C. plutellae developing inside the primary host. Contrary to earlier reports, no evidence of intraspecific variations in ability to hyperparasitize between these two populations of O. sokolowskii was found.

Knowledge on reproductive strategies and host use in insect parasitoids is fundamental for biological control purposes. Superparasitism and multiparasitism, oviposition in a previously parasitized host by a female of the same or different species, respectively, may impact pest management decisions. Our objective was to determine the occurrence of superparasitism and multiparasitism in three species of native larval−pupal solitary endoparasitoids that attack Anastrepha Shiner species (Diptera: Tephritidae) in the Neotropical region, and the possible effect on offspring fitness parameters. Doryctobracon crawfordi (Viereck), Utetes anastrephae (Viereck), and Opius hirtus (Fischer) occur in sympatry in Mexico, and are currently under consideration for use as biocontrol agents. Experiments were conducted under laboratory conditions with females acting alone (self-superparasitism), females in groups of the same species (conspecific superparasitism), and females in mixed groups (multiparasitism). Our results showed that self-superparasitism is an uncommon strategy in the three native species and is rare under conditions of intraspecific competition. In the case of multiparasitism, a higher number of immature stages of U. anastrephae was observed, compared to those of D. crawfordi and O. hirtus. However, it is not clear yet if this was due to some adult female trait or to the competitive ability of the larvae. We conclude that most females of the native species studied appeared to avoid superparasitism, specifically when acting alone, suggesting a high discrimination ability, which is probably a result of a close relationship and evolutionary history with Anastrepha hosts.