Studies were made of populations of adult Rhyssa persuasoria (L.) from various geographical regions. Morphometric analyses were based on the relative size of 32 maculae on various sclerites and the colour of the coxae and legs. Size was determined by measuring the wing length and thorax length. Various statistical procedures were applied to these data and also the ratios of wing length: maculation, and thorax length: maculation in an attempt to distinguish races of R. persuasoria from different localities. Regression analysis, analysis of variance and classification procedures separated some populations from others, the results of the different analyses being in broad agreement with each other. Within each population, maculation was typically linear, smaller specimens having relatively small maculae. Some sexually dimorphic differences were also demonstrated. There were two major geographical groupings: S.W. European and North African (W. France, Spain, Portugal and Morocco) and the remainder. There were some geographical differences within the remaining populations although all had links with one or more adjacent populations. The degree of maculation was shown to be related to the colour and texture of host-tree species, populations with low maculation scores being associated with tree species having dark, fissured bark and vice versa. It is suggested that degree of maculation is an expression of cryptic colouration, providing camouflage from predators. Determinations of heat-coma temperature for male R. persuasoria from climatically different areas showed that the response to high temperature differed between populations and was correlated with the temperature of the locality of origin. These differences between strains were apparent after several months of identical conditioning and are probably genetically based.

In April 1947, the laboratory stock of Glossina palpalis, R.-D., puparia collected from the Kaduna area suddenly became heavily infested with the pupal parasite, Syntomosphyrum glossinae, Wtstn. Presumably an infected pupa had been brought in from the bush and a few parasites had emerged undetected; it was not until the emergence of their offspring that the mass-infestation was revealed.

The following nine new species of Culicidae have recently been received by the Imperial Bureau of Entomology; the types have been presented to the British Museum.

Adults of Strategus aloeus (L.) were shown to be capable of supporting Baculovirus oryctes replication. This was confirmed by serology and by restriction endonuclease analysis. Although bioassays were not performed, the quantity of virus produced was similar to that produced in Oryctes rhinoceros (L.) and should encourage further trials on the potential of this virus to control S. aloeus. Scapanes australis (Boisduval) and Papuana biroi Endrödi did not support adequate virus replication. Previous findings on the susceptibility of O. monoceros (Olivier) were confirmed.

A general survey of coconut plantations in Guyana in 1976 indicated that in the total area of about 18 700 ha, 1000 of the 3000 ha of coconut palms on the east coast of Demerara were infested by Azteca sp. Detailed crop loss assessments on four plantations in 1970–72 indicate that the overall loss of crop to this pest in Guyana in 1976 was about 3·7 million coconuts, valued at G$372 000. Damage is partly due to mealybug, Nipaecoccus nipae (Mask.), and scale insect, Aspidiotus destructor Sign., colonies maintained by the ants and may also be partly attributed to interference with pollinating insects. Chemical control with aldrin and dieldrin sprays applied to tree trunks to create insecticide barriers and applied to whole trees with a power-sprayer and extension lance did not give adequate long-term control. Baits based on minced bovine intestine with 2% v/w ethyl alcohol were therefore assessed in field trials. Aldrin at 0·3–2·4% a.i., nonachlor at 0·3–2·0% and mirex at 0·05–0·6% were tested. Bait containing 0·1% mirex gave best results with complete kill of ants' nests 60 days after application at about 5 kg bait/ha. Mealybug and scale infestations were also eliminated by this treatment with subsequent reductions of leaf-yellowing and increases of leaf number 100 days after treatment. Up to September 1976, 0·15% mirex bait had been used to control Azteca sp. on 200 ha of coconut palms in Guyana.

As a basis for future investigations on the development and the nature of resistance against insecticides, the regression lines for the toxicity of γ-hexachlorocyclohexane to D. melanogaster were estimated by means of

1. A contact method, in which the insects (adults) were exposed to a treated surface.

2. A skin-application method, in which measured doses of an acetone solution of the poison were used.

3. An injection method in which adults were injected with known doses of an emulsion containing the insecticide.

The reproducibility of the results obtained with the above methods is briefly discussed. It was found that in the case of the skin-application and injection methods the regression line did not deviate significantly from linearity. The same was true for the contact method if the results obtained with the smaller doses were not taken into consideration.

The third-stage larva of Chalcosoma atlas (L.) collected in Malaysia is described, with illustrations, and a key is provided to distinguish larvae of this species from those of Oryctes rhinoceros (L.) and Xylotrupes gideon beckeri Schaufuss, all of which occur in similar breeding sites.

An experiment was carried out in 1967 to assess the effects and economics of aerial applications of pyrethrum as an aerosol spray against a high density tsetse population consisting mainly of Glossina pallidipes Aust. in northern Tanzania. Complete eradication was attempted, and six applications of a 0·4% w/v solution of natural pyrethrins, synergised with 2% piperony1 butoxide in power kerosene, were applied at three-week intervals over three square miles. Application was from a Cessna 182E fitted with one Micronair rotary atomiser. Populations of G. pallidipes, assessed from fly-path catches, were reduced 95% after three applications. The final three applications had little effect and it was considered that unfavourable meteorological conditions and full leaf cover were the main factors responsible. It is suggested that, in view of the high initial kill of the fly and the possibility of using pyrethrum economically against tsetse for human settlement schemes, further work should be carried out with this insecticide.

Eupelminus tarsatus, Waterst. (1916).

Eupelminus tarsatus, Waterston, Bull. Ent. Res., vi, Feb. 1916, p. 389, figs. 7 and 8 ; Lamborn, ibid., vii, May 1916, p. 34.

A series of both sexes of this parasite of Glossina morsitans enables me to describe the male for the first time and the female more fully. One of the striking features about this species, apart from its remarkable sexual dimorphism, is the great range in size which it exhibits. The females run from 3½ mm. to 5 mm. and the males from 1½ mm. to 2¼ mm., with a range in the alar expanse of 2¼ mm. to 3¾ mm. The larger female examples are invariably darker and more metallic in coloration. Dr. Lamborn is certainly right in correlating the smaller size of some of the parasites with a reduced food supply (l.c. p. 35). I cannot yet agree, however, that the parasitic status of E. tarsatus is definitely fixed by our present knowledge of its habits. Plainly the proportion of Mutilla-parasitised puparia supplied to the Eupelminus females was larger than could have occurred under natural conditions. Again, the factors, whatever they are, inducing Mutilla to oviposit in a particular puparium may be equally decisive for the female Eupelminus. If, for example, in two cases three Eupelminus punctures all close together could be seen with a high-power lens one might suggest that some structural peculiarity invited the attack. Nor, incidentally, is it legitimate to infer that because a puparium observed to be stung produced no Eupelminus the attack had failed. The presumption is that the attack had not been delivered, stinging and ovipositing being, in many cases, two separate processes. Many Chalcids plunge the ovipositor into ova, puparia, etc., and then, applying the mouth to the wound, suck up the contents which have been expelled. In other cases the first stinging observed is merely the narcotising and rendering antiseptic of the host, which precedes the real introduction of the ova. The parasitic status of Eupelminus can, in fact, be settled only by examination of puparia, collected under natural conditions, from which the Chalcids have been noted to emerge.

Three-day-old virgin females of Glossina austeni Newst. that had emerged in the laboratory in Britain from wild puparia collected in Africa or from subsequent laboratory cultures were caged with males over nine days old for 24 hours and dissected after death. Of the 5,474 flies so treated, 38 per cent. died within 14 days after mating day, whereas of the 593 found to be uninseminated, 73 per cent. died during that period, mostly within the first six days. A possible explanation of the discrepancy is that females with a poor expectation of life are unattractive to males, and this could account for the very small proportion of uninseminated flies in field collections, since such flies would tend to die before they could be captured.

An analysis of detailed observations on flying swarms of the Desert Locust, S. gregaria, on 33 occasions in eastern Africa has demonstrated an association of intermittent flight with higher and of continuous flight with lower saturation deficits. This association, which is consistent with recent laboratory studies on the effects of atmospheric humidity on the flight-performance of suspended locusts, is discussed in relation to the rate of movements of migrating swarms.

The black rice bug, Scotinophara lurida (Burm.), is widely distributed in Ceylon in areas where rice is grown under irrigation. It first became a serious pest in 1940 and, periodically since, it has assumed epidemic proportions in the Southern Province where two crops of rice are grown annually. Each crop takes from 3½ to 4 months to mature, the fields lying fallow in the intervening periods. During these periods the insects aestivate, in the adult or late nymphal stages, in cracks in the bunds in the rice-fields or on neighbouring higher ground. They remain motionless for the most part during aestivation, are gregarious and occur as much as 2 ft. below ground-level.

The adults leave the aestivation sites in April and May and settle in the first crop when it is two to three weeks old, and a subsequent aestivating population behaves similarly in November and December for. the second crop. There is at first considerable flight activity at dusk, and at night, and after feeding for about a week on the rice seedlings copulation takes place and oviposition commences about ten days later.

A new easily-produced cheap compound for use as a bait matrix is described. The light-weight matrix of polyurethane is prepared from dense precursors into which suitable attractants and toxicants can be incorporated for the pest species in question. It has a high bait effectiveness/weight ratio, and so is very suitable for aerial application as large economically viable payloads can be achieved. When tested both in the laboratory and in the field on a small scale against the leaf-cutting ant Acromyrmex octospinosus (Reich), the bait was highly acceptable to the ants. Some formulations, especially those coated with mirex gave excellent control of ants in the field in Trinidad, killing all occupants of nests within four days of baiting. The bait exhibited good weathering properties, was resistant to fungus attack, and allowed the slow release of pheromones. It was much cheaper than the citrus pulp baits normally used in Trinidad.

The description of the ten Chamaesphecia species associated with Euphorbia in eastern and south-eastern Europe is based on external adult morphology, male and female genitalia, and the structure of the egg chorion. These species can be divided into two groups according to the shape of the setae of the dorso-basal part of the valvae in the male genitalia. Most Chamaesphecia species are associated with one species of host-plant and all are closely tied to one habitat type. The host-plant and the structure of the egg chorion are fundamental characteristics for the determination of a few species, and very helpful for the others. All species bore into the main root of their host-plant and overwinter as larvae. With the exception of two species which have an annual or biennial life cycle, all species are univoltine. The larvae of three of the eight Chamaesphecia spp. investigated feed and develop in the roots of North American leafy spurge, Euphorbia esula sensu lato. Of these, the best candidate for the biological control of leafy spurge is C. crassicornis, because the larvae have a similar survival rate on the target weed and the European host-plant, E. virgata.

Populations of Liparus glabrirostris (Curculionidae: Molytinae), a weevil inhabiting higher altitudes of Central Europe, were sampled from 24 localities in the Alps and Carpathian Mountains, and the geographical structuring of genetic variation was analyzed. Comparison of the concatenated mitochondrial cytochrome oxidase subunit I and subunit II sequences revealed consistent genetic divergence between the populations of L. glabrirostris from different mountain ranges. In phylogenetic analysis using maximum parsimony and median-joining networks, concatenated mitochondrial haplotypes from the Alps and Carpathians clustered as separate lineages, with high bootstrap support. Substantial genetic distances determined between the separated groups ranged from 2.6 to 3.0%, with divergence estimated to have initiated approximately 0.85–0.98 million years ago. The nuclear elongation factor 1α gene was additionally amplified and haplotype analysis showed very low evolutionary divergence (0.2%), with separate clustering as well. The observed divergence suggests that the populations have been isolated for a long time, as a consequence of environmental changes resulting in varying fragmentation of habitats in the Alps and Carpathians, interrupting genetic exchange events and altering the genetic structure of L. glabrirostris populations. On the other hand, comparison of morphological characteristics showed no differences to confirm genetically well differentiated groups of populations. A polymerase chain reaction and restriction fragment length polymorphism-based method was therefore developed to discriminate between the Alpine and Carpathian lineages.

Scale of adult ♀ about 2 mm. long, moderately broadened behind, convex, usually curved, white, not glossy, but with ± conspicuous growth-lines; exuviae orange-brown to dark brown. The colour of the second exuviae is only slightly obscured by a faint secretionary covering.

The following article has been written from notes of observations and experiments extending over nearly three years—April 1909 to December 1911. Its main object is an attempt to demonstrate that a true conception of the production of Auopheline mosquitos in a definite country or district can only be formed by a large amount of continual work throughout the seasons of the year. At the present time very numerous observations are still to be made before much generalising should be allowed concerning the breeding-grounds and bionomics of these insects.

Collections of Cactophagus spinolae (Gylh.) were made in Mexico in 1946, 1947, and 1948 to supplement the biological control of prickly pear (Opuntia spp.) in South Africa. During these three years, 862, 1,396, and 15,584 adults, respectively, were dispatched to South Africa. The weevils were sent by air express in specially designed containers, and arrived in excellent condition.

This paper includes information on the distribution, life history and food preferences of C. spinolae. The need is stressed for anticipating the effects of transit conditions upon living insect material transported by aircraft.

Phenacoccus avenae Borchsenius, a mealybug described originally from beneath the leaf sheaths of a grass in Armenia, USSR, has been intercepted at quarantine in the Netherlands. USA and England on bulbs, corms and rhizomes of ornamental plants from Turkey. The mealybug, however, has never been recorded from Turkey although it probably exists there on monocotyledons. It is redescribed and illustrated here to facilitate identification at quarantine stations, and a list is given of its host-plants in the families Gramineae, Amaryllidaceae, Iridaceae and Liliaceae.

An experiment was designed to ascertain the maximum yield of adults of the Cigarette Beetle, Lasioderma serricorne (F.) that could be reared from a given quantity of foodstuff. Equal numbers of eggs of this species were added to batches of tubes containing different weights of wheatfeed, and the resulting adults were removed, counted and weighed.

The weights of wheatfeed had been chosen so that in some of the batches of tubes it would not be completely exploited. When emergence of adults was complete, further numbers of eggs, which were calculated to produce approximately the number of larvae necessary to complete the process in each batch of tubes, were then added, and the resulting adults again removed, counted and weighed.

The maximum biomass (wet weight) of adults of L. serricorne which could be reared from egg to adult per gramme of wheatfeed at 25°C. and 70 per cent. relative humidity was found to be 0.214 g. (108 to 129 specimens, all more or less undersized, and many with a retarded rate of development, compared with insects given ample food). In addition to the 21 per cent, of the food converted into adult insects, another 27 per cent. by weight of the original foodstuff was lost, presumably as water and carbon dioxide, leaving just over 50 per cent. undigested residue, most of which was faecal matter that would have passed through the insects at least once.

The yield of insects per g. loss of weight of the foodstuff was 0.46 g. (wet weights), which is very close to the corresponding figures calculated from the results of Fraenkel & Blewett for Dermestes maculatus Deg., Tribolium confusum Duv. and Ephestia Kuehniella Zell. on various foods, but three times as great as the corresponding figure calculated from Richards' results for Calandra granaria (L.) in wheat.

There was evidence suggesting that a truly maximal yield (slightly greater than in these experiments) might be attained by adding an optimal number of eggs to the food at the start, instead of adding a second population to an incompletely exploited food supply.