The importance of certain species of Stomoxys in Uganda, the possibility that these species may be responsible for the mechanical transmission of trypanosomiasis, and the effects of severe biting of Stomoxys on cattle causing loss in milk yields and weight in beef animals, is pointed out.

A satisfactory method is described for rearing large numbers of Stomoxys calcitrans (L.) under the conditions that prevail in East Africa.

A description of special cages for keeping the adults and for egg production is given, together with a technique for supplying the adults with 0·2 per cent, citrated bullocks' blood.

A satisfactory egg-laying and breeding medium contained 9 oz. of dried cow dung, 5 oz. of dried blood granules and 1 oz. of sugar.

A detailed description of the construction and working of a constant-temperature and humidity room for rearing larvae and pupae is given, the temperature and relative humidity of the room being maintained at 90°F. and 90 per cent., respectively.

The maximum number of eggs that can be introduced into 1-lb. and 2-lb. Kilner jars without causing overcrowding and subsequent under-nourishment in the later larval instars was found to be 200 and 400, respectively.

In the following descriptions I have dealt mainly with part of a small but valuable collection of Coccid Chalcids, sent by Mr. W. H. Patterson from Aburi, Gold Coast. The excellent condition in which the insects were received may be due to some extent to the fact they were bred specimens, but it also owes something, I think, to the method of packing employed. Into each tube (1¾in. × ½ in. ) a little melted naphthalene had been run with a piece of moderately thick paper on the top ; above this again the Chalcids were loosely enclosed in screws, or (in the case of minute Eulophids and Aphelinines) in small triangles of tissue paper, and the tube coated and sealed with paraffin wax.

During the course of an investigation having as its object the control of Thrips imaginis, Bagnall, a pest of deciduous fruit blossom in Australia, it has been found necessary to make numerous counts of the number of these insects found infesting various flowers. These counts are made for two purposes, the principal one being the determination of the effect of attempted control measures. In addition, counts are taken every day throughout the year for the purpose of following the seasonal fluctuations of the numbers present in the field.

At the beginning of the investigation, flowers were picked, placed in closed cardboard cylinders and taken into the laboratory. Each blossom was then examined separately for thrips, the insects being captured by means of a moistened camel-hair brush, with which they were transferred to a small dish of 70 per cent. alcohol. This method was slow and not particularly dependable, as on hot days when the thrips were active, as soon as a flower was placed on the laboratory bench, numbers of insects would leave it and make off in all directions, even taking to flight.

As a result of the unsatisfactory nature of the procedure described above, an apparatus has now been devised which is saving both in time and patience, and gives reliable results (fig. 1). It consists of a glass cylinder 5 inches in diameter and 10 inches high. The top is closed with a close-fitting lid.

Screened and unscreened eucalyptus trap-logs infested by Phoracantha semipunctata (F.) were used to examine the excavating habits of the Syrian woodpecker (Picoides syriacus), its annual course of predation and its effect on the survival rate of Phoracantha semipunctata larvae in Israel. The bird excavated predation holes only in trap-logs with larvae within the bark. Predation holes density increased during the spring and summer. Towards the autumn, egg-masses were killed too. The average mortality due to predation was 29·21% of total larval mortality and 78·7% among larvae that survived intraspecific competition. The mortality caused by the woodpecker decreased with increasing density of larvae. The natural control of P. semipunctata in Israel and the borer-woodpecker ecosystem are discussed.

Host choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25°C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat‘s presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50–70% decline in the initial number of adult fleas during the first week after their release onto a rat host, and this decline was greatest on juvenile rats. Flea fecundity was also significantly lower on juvenile rat hosts but no differences due to the sex of the rat were observed. This experimental study supports the hypothesis that differences in flea count due to host sex, reported in field surveys, result from sexual differences in host behaviour and not from discriminatory host-seeking behaviour by X. cheopis. Differences in flea count due to host age may be affected by differences in X. cheopis fecundity, which may itself be mediated by host behaviour such as grooming.

Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.

The biology of Paropta paradoxus (H.-S.), a new pest of the grapevine, was studied in field and laboratory during 1962–1972. Descriptions are given of the imago and developmental stages. The life-cycle is completed in 1–3 years. Adults are active during April–September, and eclose mostly during the day with a male/female ratio of 0.65 (3.3 in UV light-trap catches). Light induces a deep torpor in most adults. After mating, which lasts 30–60 min, females lay up to 275 eggs in their life span of 1–14 days (males 2–13 days). In the vineyard eggs are glued under loose bark, in batches of 15.6 (1–63), and hatch in 20–32 days. The neonate larvae disperse and settle under loose bark where they begin feeding; penetration of the wood is mainly through dried stubs of pruned canes, and galleries are excavated along the axes of stems and branches. Larvae may also develop under dry bark. The pest overwinters as active immature larvae and diapausing mature, prepupal larvae. The pupa is usually formed in the larval galleries, and lasts 16–45 days. In heavily infested vines the pupae may be cannibalized by larvae; both larvae and pupae may be preyed on by woodpeckers.

Hungry tsetse flies (Glossina morsitans Westw.) are confined individually on the stretched wing membrane of a bat. Only 10–20 s after the tarsi touch the membrane, the flies probe and salivate, the main saliva flow following after penetration. The clear colourless saliva is easily collected onto a microscope slide.

The effects of piperonyl butoxide on the toxicity to adult mosquitos (Anopheles stephensi List, and Aedes aegypti (L.)) and house-flies (Musca domestica L.) of pyrethrins, two synthetic pyrethroids, three organophosphorus compounds and their oxygen analogues, and three carbamates (Sevin, and both 3-isopropylphenyl and 3,5-di-isopropylphenyl N-methylcarbamate) were determined quantitatively. Solutions, in di-isobutyl ketone, containing insecticide alone and insecticide/ piperonyl butoxide mixtures in the proportion of 1:10 were applied topically to individual insects.

A high degree of synergism was obtained only with natural pyrethrins and carbamates and house-flies, and the effect on the toxicity of these insecticides to adult mosquitos was much less pronounced. Insecticidal potency of the synthetic pyrethroids allethrin and dimethrin was influenced less than that of natural pyrethrins.

Piperonyl butoxide antagonised the action of malathion in M. domestica, and to a slight extent in A. stephensi, but increased the toxicity of malathion and malaoxon to Ae. aegypti. It had little effect on the potency of diazinon and parathion and their oxygen analogues (diazinoxon and paraoxon) with the exception that it increased the toxicity of diazinon and diazinoxon to Ae. aegypti.

The results are discussed in relation to the hypothesis that piperonyl butoxide inhibits detoxification in insects. From a practical point of view, they suggest that no great advantages would be derived from the addition of piperonyl butoxide to formulations of organophosphorus compounds and carbamates used for residual contact action against adult mosquitos.

To explore the characteristics of the mitochondrial genome (mitogenome) of the squeaking silkmoths Rhodinia, a genus of wild silkmoths in the family Saturniidae of Lepidoptera, and reveal phylogenetic relationships, the mitogenome of Rhodinia fugax Butler was determined. This wild silkmoth spins a green cocoon that has potential significance in sericulture, and exhibits a unique feature that its larvae can squeak loudly when touched. The mitogenome of R. fugax is a circular molecule of 15,334 bp long and comprises 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and an A + T-rich region, consistent with previous observations of Saturniidae species. The 370-bp A + T-rich region of R. fugax contains no tandem repeat elements and harbors several features common to the Bombycidea insects, but microsatellite AT repeat sequence preceded by the ATTTA motif is not present. Mitogenome-based phylogenetic analysis shows that R. fugax belongs to Attacini, instead of Saturniini. This study presents the first mitogenome for Rhodinia genus.

Alatae of Myzus persicae (Sulz.) were made to fly and then released directly onto untreated or chemically treated surfaces where settling behaviour was studied. Most aphids probed host-leaf surfaces even in the presence of vapour of (E)-β-farnesene, the main component of aphid alarm pheromone, or when related behaviour-controlling chemicals were painted on the leaf. Flown aphids attempted to probe most surfaces on which they landed, including glass and green paper. However, they did not probe white filter papers. Sublethal deposits of deltamethrin did not prevent initial probing on plant surfaces but caused uncoordinated leg movements which resulted in aphids falling from the plants.

Pareuchaetes aurata aurata (Butler) from Chromolaena jujuensis in northern Argentina was tested as a biological control candidate for the composite weed C. odorata. The larvae feed voraciously and complete their development on C. odorata. The host-plant feeding range of P. a. aurata is limited to the genus Chromolaena. It is suggested that the egg-laying behaviour of P. a. aurata, which scatters its eggs around the base of the host-plant, will help to overcome the problem of ant predation which prevented the establishment of Pareuchaetes pseudoinsulata Rego Barros, which lays its eggs in batches, in South Africa. Any possible benefits of the new association between P. a. aurata and C. odorata may also contribute to the success of this biological control programme.

An investigation was made into means of increasing the effectiveness of the usual DDT-containing residual sprays with a kerosene base.

The common house-fly, Musca domestica, was used as biological material.

It was found that there exists a distinct relationship between crystal size and residual toxicity. Finely crystalline residues from DDT solutions in volatile solvents, such as xylene, proved to be considerably more toxic than coarsely crystalline residues from DDT solutions in less volatile solvents, such as kerosene. Addition of small quantities of coumarone resin to a DDT solution in kerosene was found to reduce the size of the DDT crystals and to increase the toxicity considerably.

The preponderance of males in tsetse-fly catches is an interesting fact that has not been understood in the past. Attention is drawn to the importance of the agefactor. Teneral flies are nearly always taken in equal numbers whereas non-teneral A.G.I flies and A.G.2 flies have the highest male/female ratio. In A.G.3, the ratio drops, indicating a decline in reproductive capacity. Females become fugitive about seven days after emergence, at the time when the first egg is almost due to descend into the uterus, i.e., at the end of the teneral stage. This is the mating phase par excellence. Mating is prolonged, vigorous, and frequent, and this accounts for the early appearance of the mating scars. As the uterus lies under and between the mating cushions, it is unsafe for females with eggs in the uterus or young larvae to mate. Third-instar larvae are safer as the highly chitinized polypneustic lobes take the brunt of the pummelling from the claspers. Safe periods also occur during the hiatus between larvipositions when the uterus is empty. There are, of course, other factors influencing the ratio, but the age factor is considered paramount, and failure to recognize this in the past has resulted in a good deal of confusion.

Rhaconotus mahensis, sp. n.

♀♂. Black ; scape and all legs red testaceous ; ovipositor bright red ; flagellum red-brown, possibly rather darker at apex ; wings hyaline, the setae with a distinctly fulvous tinge, and the stigma hyaline (at least not darkened).

♀♂. The integument is not coriaceous throughout, and is only sparsely clothed with setae (except on the flagellum and possibly the legs). Head smooth and highly shining, not coriaceous, impunctate, the vertex and occiput almost entirely devoid of setae ; antennae longer than head, thorax, and abdomen together ; flagellar joints in ♀ 29–33, in ♂ 26–28. Thorax : mesonotum dully shining, coriaceous ; the notauli well marked, joining slightly before reaching the posterior margin of the mesonotum ; propodeon with five longitudinal carinae, one in the middle and two on each side, these latter rather more closely placed to each other than to the median carina ; this median carina is discernible as such only in the basal half of the propodeon, thereafter becoming lost amongst the reticulate wrinkles with which the apical half of the propodeon abounds ; the lateral carinae, on the other hand, are discernible more or less throughout their length, particularly the inner pair which can generally be traced to the median apex of the propodeon where they join each other ; the integument of the basal half of the propodeon coriaceous on each side of the median carina as far as the first lateral carina, thereafter wrinkled as in the apical half.

Epidemiological studies of Rhodesian sleeping sickness and its vector Glossina morsitans Westw. were made near Motsowi in the western floodplains of the Okovango Swamps, Botswana, during 1967–68. The low apparent densities of the fly (12–27 in three fly rounds compared with 124 in a fourth located in a more densely forested area to the east) and low recapture rates (1·3–3·9%) indicated the Motsowi area to be a feeding ground. Peak densities in January and troughs in October reflected seasonal movements of the fly to and from their dry-season retreats to the east. Most bloodmeals (61%) were on warthog, but 5·5% were on reedbuck in which the Trypanosoma brucei infection rate was 33%. In the Motsowi area the total trypanosome infection rate in G. morsitans was 5·7%,, with T. brucei 0·6%, but the rate varied between localities elsewhere in the Okovango. Man's movements into the fly areas to the east offer the main pathway for transmission of T. brucei, perhaps aided by seasonal movements of reedbuck closer to the settlements. The incidence of human trypanosomiasis is therefore unlikely to be reduced by insecticide campaigns in the farming areas, but livestock will benefit from a reduction in cattle trypanosomiasis.

In tests in Nigeria with its principal host-plant, cowpea, Cydia ptychora (Meyr.) showed distinct oviposition preferences. Most of the eggs were laid on the sepals (including their remains on pods) in screenhouse tests involving four varieties. There were distinct differences in the number of eggs laid on different varieties in both no-choice tests with four or five varieties and free-choice tests with 17 varieties in the field. Vita-3 was the preferred variety in the laboratory tests and H 13–1 in the larger comparisons in the field. Fewest eggs were deposited on Tvu 2994 in all tests.

Five strains of Culex pipiens L. (four resistant and one susceptible) were compared at the fourth larval instar for tolerance to organophosphate, carbamate and pyrethroid insecticides, with and without the addition of three synergists (piperonyl butoxide, triphenyl phosphate (TPP) and S, S, S-tributyl phosphorotrithiote (TBPT)). The DAR/D strain from Tanzania showed the highest levels and broadest range of resistance (temephos 37 ×, malathion 579×, propoxur 3032× and permethrin 100×). A strain from Rangoon and two from France (S54, BLEUET) showed lower resistance, restricted to organophosphates. Temephos and malathion resistance in the RANGOON strain was strongly inhibited by TBPT but not by TPP or piperonyl butoxide. Temephos and permethrin resistance in the DAR/D strain was slightly inhibited by TBPT and permethrin resistance by piperonyl butoxide. The DAR/D, RANGOON and CfCA (susceptible) strains were also compared for general esterase activity and phosphatase activity, both of which were higher in the resistant strains. It is concluded that resistance in RANGOON is associated with high production of an esterase sensitive to inhibition by TBPT but with little or no sensitivity to TPP, resembling but not identical in properties with the enzyme in strain S54 investigated earlier. Resistance in DAR/D was also associated with some increase in esterase activity, but the basis of resistance was different from that in S54 and RANGOON, having a much lower sensitivity to inhibition by TBPT.