On the basis of specimens from New Guinea and New Britain, the genus Dynamenais Kirkaldy (Pyrrhocoridae) is re-defined, four species and one subspecies are described in the new subgenus Syncrotus (Syncrotellus) (Pyrrhocoridae), and two species are described for the new genus Goilalaka (Pentatomidae). S. (S.) similis sp.n. was recorded from cacao, and S. (S.) madanganus sp.n. and G. rubroruga sp.n. from Solanum spp.

Limewashes containing DDT or “Gammexane” were tested for insecticidal action on mosquitos (Aëdes aegypti) by confining the latter in cages with treated walls and ceilings. Only about 60 per cent, of the total internal surface of the cages were treated but the mosquitos were averse to settling on the floor, window, etc., which constituted a large part (28 per cent.) of the untreated area.

Limewashes containing 160 mg. DDT per square foot gave a high kill of mosquitos after two hours' exposure in the cage; and 8 mg. per square foot of the active principle of “Gammexane” gave a high kill with a one hour exposure.

Both treatments remained effective for 6–8 weeks under temperate conditions.

The following notes and descriptions are based on material received by the Entomological Research Committee, who have kindly presented the types of the new species to the National Collection.

A new genus Mesobraconoides Sarhan & Quicke is described for the species M. psolopterus (Wilkinson) comb. n. (type species) and M. truncatus (Szépligeti) comb. n. Both species have been transferred from Mesobracon. M. psolopterus is here recorded from Sierra Leone as a parasitoid of the pyralid, white rice borer, Maliarpha separatella Ragonot, widespread in the Afrotropical region. M. psolopterus is redescribed and illustrated and a key provided to separate it from M. truncatus.

Each season since 1918 numbers of leaf-feeding sawfly larvae have been taken during the months of June and July in both oat and wheat crops. The larvae feed along the edges of the blades during the day and usually cut off the upper portion.

In this experimental analysis of the teratology of Tribolium, we studied the effect of crowding and handling on a disorder associated with pupal eclosion. Handling increased the incidence of the abnormality which occurred infrequently in controls: the crowding level tested by us had no effect. T. confusum Duv., strain b-I produced more abnormal beetles than T. castaneum (Hbst.), strain c-IV-a. Handling older pupae increased the disorder to a greater extent than in young and non-pupae.

The handling procedure was quite vigorous and the threshold level required to produce the effect is not known. The phenomenon might be important in population ecology but the pathway through which handling produces it is unknown.

Observations on the behaviour of Culex pipiens fatigans Wied. were made in 24 huts built and occupied by Africans on a sisal estate near Tanga, Tanganyika Territory. Catches were made in four huts each day, an exit trap being fixed on the window from 2 p.m. to 6 p.m. (evening trap) and replaced by another from 6 p.m. to 8 a.m. next day (morning trap), when a spray catch was made of the mosquitos still in the hut. Each hut was used only once a week, for 31 weeks, from December 1952 to July 1953. The females caught were sorted according to the stage of the gonotrophic cycle, as judged by external examination. The stages used were: I, no blood, no visible ovaries; II, stomach full of blood, ovaries small; V, little or no blood, ovaries fully developed; III and IV, intermediate between II and V.

An analysis of variance was performed on the results. Catches of both sexes showed a significant variation with time, which was not, however, correlated with rainfall. Significantly different numbers were taken in the traps and in the huts. Females were significantly most numerous in the hut catch, and males in the morning trap, the former result suggesting that most females spend more than one day in a hut. There were significant differences between the numbers of females in the different stages of the gonotrophic cycle, stages I and II together accounting for 80 per cent, of all females caught. The high proportion of stage I is attributed to delay between emergence and feeding, and of stage II to the taking of more than one meal during the gonotrophic cycle, later meals obscuring the state of ovarian development. There were significant differences between huts as regards the numbers of females caught, but not as regards males, and it is concluded that this is due to variations in the attractiveness of the inhabitants of the huts.

Females in stage I were most numerous in the morning trap, those in stages II–IV were taken only rarely in traps, but there was no significant difference between numbers of stage V caught in huts and in the two window traps. These results arse attributed to restlessness in both hungry and gravid females, and sluggishness in fed ones. All stages except III were significantly more numerous in some weeks than in others and this might be due to variations in either rate of reproduction, or rate of loss of mosquitos from huts. There were significant variations in behaviour in different weeks. For females, this is attributed to changes in the proportions of the stages with time and the dependence of behaviour on stage. For males, there is some evidence of a relation between behaviour and humidity outside the hut. For females, the distribution of stages between different places of capture changes with time, stages II and III being most consistently associated with hut catches, while the most variable behaviour is shown by stage V.

The necessity for behaviour studies on mosquitos in the field is pointed out, especially in relation to field trials of residual insecticides.

When DDT and “Gammexane” were first used in Uganda for work on tick control, the absence of a rapid and simple chemical test made it necessary to evolve a biological method which would assess the killing power of the preparations in use. Such a method, if it is to be employed to assess the results of field work, should satisfy the following conditions;

(a) ticks should receive an initial wetting with the preparation comparable to that received when cattle are dipped or sprayed, and

(b) remain on a moist surface for a few hours, and then for a longer period in contact with the dried deposit, as in the case of the animal after it has been dipped or sprayed.

♀ Head: sides clothed with flat white scales, interrupted by a rather narrow horizontal band of flat black ones; two large patches of flat black scales on the top, separated by a rather narrow band of narrow white scales extending from the nape on to the front; a narrow line of narrow white scales bordering the upper part of the eyes. Eyes well separated. Proboscis and palpi black. First antennal joint blackish, greypruinose. Thorax: integument blackish, except for the reddish scutellum and a small pale spot on each side at the base of the postnotum. Prothoracic lobes and the space behind them clothed with flat white scales. Scutum clothed with narrow yellowish-white and blackish scales, the former arranged in definite narrow lines as follows: a median line extending from the front margin to a little in front of the scutellum, where it forks into two; a line on each side of this extending the whole length of the scutum, enlarged a little in front of the middle and sending a branch obliquely forwards from this point to the lateral angle of the thorax; and another line forming a border to the scutum. Scutellum with narrow scales, mostly yellowishwhite, but some black ones on each side of the middle lobe. Pleurae with several patches of flat white scales. Abdomen black, above with conspicuous pure white basal lateral patches and traces of yellowish-white basal bands on all the segments; venter black, all the segments with pure white basal bands. Eighth segment welldeveloped, only partly retractile; cerci short, rather broad and rounded at the tip.

The surfaces of bags containing fumigated cocoa were sprayed with the macrodosage of 956 mg./sq. ft. DDT applied as a 5 per cent, suspension of wettable powder in water.

After exposure to an infestation of Ephestia cautella and Tribolium castaneum, no appreciable effect was obtained in preventing an attack by E. cautella, though the larvae appeared to choose unusual pupation sites on the surface of the bags. T. castaneum were rapidly affected and prevented from entering into the sacks.

Aphis spiraecola Patch is one of the most economically important tree fruit pests worldwide. The pyrethroid insecticide lambda-cyhalothrin is commonly used to control A. spiraecola. In this 2-year study, we quantified the resistance level of A. spiraecola to lambda-cyhalothrin in different regions of the Shaanxi province, China. The results showed that A. spiraecola had reached extremely high resistance levels with a 174-fold resistance ratio (RR) found in the Xunyi region. In addition, we compared the enzymatic activity and expression level of P450 genes among eight A. spiraecola populations. The P450 activity of A. spiraecola was significantly increased in five regions (Xunyi, Liquan, Fengxiang, Luochuan, and Xinping) compared to susceptible strain (SS). The expression levels of CYP6CY7, CYP6CY14, CYP6CY22, P4504C1-like, P4506a13, CYP4CZ1, CYP380C47, and CYP4CJ2 genes were significantly increased under lambda-cyhalothrin treatment and in the resistant field populations. A L1014F mutation in the sodium channel gene was found and the mutation rate was positively correlated with the LC50 of lambda-cyhalothrin. In conclusion, the levels of lambda-cyhalothrin resistance of A. spiraecola field populations were associated with P450s and L1014F mutations. Our combined findings provide evidence on the resistance mechanism of A. spiraecola to lambda-cyhalothrin and give a theoretical basis for rational and effective control of this pest species.

Ephestia kuehniella (Lepidoptera, Pyralidae) and Sitotroga cerealella (Lepidoptera, Gelechiidae) are important factitious hosts used for production of biological control agents. Their differences in terms of biology and behavior require adjustments in their mass production, particularly when using corn or barley as food in grain or in bran. We modeled adult emergence, oviposition period and egg production along time after emergence, as a function of the food source. Significant differences between hosts or food type were found for these variables and for adult weight but not for sex ratio. Our results confirm the possibility of mass production of these hosts using corn or barley as food source. Integrating adult emergence patterns and age specific fecundity patterns into a single model, it is clear that rearing E. kuehniella on barley would result in the highest egg output in much shorter time than E. kuehniella on corn or S. cerealella on barley.

Culex quinquefasciatus Say is the major vector of the filarial parasite Wuchereria bancrofti (Cobbold) which causes lymphatic filariasis in humans. A repetitive DNA sequence from the genome of C. quinquefasciatus has been cloned and completely sequenced. The 693 bp cloned fragment had an A+T content of 72%. Dot matrix analysis of the fragment did not reveal any direct or inverted repeats within it. Southern blot analysis using a variety of restriction enzymes appeared to indicate that the cloned fragment was interspersed within the genome with a copy number of approximately 30,000. A search of the GenBank database did not reveal significant homologies to any previously cloned sequences. Although the probe was sensitive enough to detect picogram quantities of DNA, it was not specific for C. quinquefasciatus, as it hybridized with DNA from other mosquito species, Culex pseudovishnui Colless, Culex gelidus Theobald, Culex tritaeniorhynchusGiles, Anopheles vagus Dönitz and Mansonia uniformis (Theobald). However PCR primers derived from the cloned sequence, IpC, were found to be specific and amplified only C. quinquefasciatus DNA. The optimized PCR assay was found to be very sensitive and was capable of detecting DNA from all stages of C. quinquefasciatusthus making it an ideal diagnostic tool.

Changes in environmental conditions influence the performance of organisms in every aspect of their life. Being capable of accurately sensing these changes allow organisms to better adapt. The detection of environmental conditions involves different sensory modalities. There are many studies on the morphology of different sensory structures but not so many studies showing their function. Here we studied the morphology of different sensory structures in the larva of a dipteran parasitoid. We occluded the putative sensory structures coupling the morphology with their function. First, we could develop a non-invasive method in which we occluded the putative sensorial structures annulling their function temporarily. Regarding their functionality, we found that larvae of Mallophora ruficauda require simultaneously of the sensilla found both in the antennae and those of the maxillary palps in order to orient to its host. When either both antennae or both maxillary palps were occluded, no orientation to the host was observed. We also found that these structures are not involved in the acceptance of the host because high and similar proportion of parasitized hosts was found in host acceptance experiments. We propose that other sensilla could be involved in host acceptance and discuss how the different sensilla in the antennae and maxillary palps complement each other to provide larvae with the information for locating its host.

Bracon ?hancocki (Wlkn.) is a larval ectoparasite of Cydia ptychora (Meyr.), a major pest of cowpea at Ile-Ife, Nigeria. Parasitism occurred in the field all the year round, varying from 0 to 65·9% and with the highest incidence from September to February. In the laboratory, the fecundity of the parasite was low, averaging about six eggs per female. The life-cycle was completed in ten days. Mating occurred soon after emergence, and the preoviposition period lasted about 2–3 days. Unmated females rarely laid eggs, and their life-span averaged six days as compared to 14 days for mated females. The female:male ratio was 2:1. The parasite rarely attacked previously paralysed hosts, and the preferred hosts were the older, larger larvae. A description of the egg and larvae is given.

Benzene hexachloride and DDT are relatively new insecticides and their veterinary value when administered orally to bovines has not yet been fully investigated.

The first series of experiments showed that 0·5 gm./kg. on two successive days of D. 929, was toxic; 0·25 gm./kg. on two successive days followed by 0·125gm./kg. on the 3rd and 4th days was well tolerated, and the benzene hexachloride remained in the blood in sufficient concentration to kill feeding tsetse and ticks up to the 41st day. After a single dose of 0·25 gm./kg. the benzene hexachloride remained in the blood for only 10 to 12 days, and failed to protect the animal from East Coast Fever when it was grazed on heavily infested pasture.

Five calves susceptible to East Coast Fever were dosed with D.929 and exposed to attack by the common tick species under African farming conditions. A dose of 0·125 gm./kg. given weekly protected a calf from East Coast Fever, but there was no protection when the same dose was given once a fortnight. A dose of 0·125 gm./kg. given weekly also protected, whereas 0·1 gm./kg. failed. At all these dosages the concentration of benzene hexachloride in the blood was sufficient to kill feeding G. palpalis during the period the calves were under treatment and for periods of 10 to 25 days after the final dose.

D.929 given to animals suffering from East Coast Fever and Trypanosomiasis had no effect on the course of these diseases.

Doses of 0·3 gm./kg. (39 mg./kg. gamma isomer) are toxic to young animals but older animals showed a greater tolerance. Hypersensitivity, muscular tremors, and general paralysis were the main toxic symptoms, and gross pathologicaal changes were most obvious in the liver and urinary system. The median lethal dose of benzene hexachloride given orally for calves is therefore lower than for small laboratory animals as recorded by Cameron (1945). Only crude benzene hexachloride powder (13 per cent, gamma) was used in the preserit experiments, but Slade (1945) has shown that this is markedly less toxic than the purified gamma powder.

Little experimental work was done with DDT as the results with benzene hexachloride were more promising both in the control of ticks and tsetse.

In Ghana, a considerable part of the main-crop cocoa is stored for six months or more, some up to nine months, and infestation by insects increases during storage. Data are given, obtained chiefly in Ashanti on the 1957–58 main crop.

Assessment by sieving the contents of whole bags and counting the numbers of adult insects found (or, in the case of Ephestia cautella (Wlk.), the larvae and pupae also) showed that at the beginning of the main-crop season (September–November), infestation was very light (1–2 insects per bag), but was present in a high proportion of the bags (46–47 per cent, in October). The species present represent those found regularly breeding in cocoa in Ghana, namely, Ephestia cautella (Wlk.), Lasioderma serricorne (F.), Araecerus fasciculatus (Deg.), Tribolium castaneum (Hbst.), Garpophilus dimidiatus (F-), Ahasverus advena (Waltl), Cryptolestes spp., and an unidentified species of Silvanid. After six months' storage, the total count averaged over 100 per bag and comprised chiefly L. serricorne and T. castaneum; larvae of Ephestia were much rarer (less than five per bag), but adults of Ephestia were abundant in the sheds after 2–3 months' storage.

Sieving proved a useful technique for obtaining data on infestation, though careful supervision of staff is required to minimise errors. Variation from bag to bag in the same ‘lot’ of cocoa is large, and estimates based on as few as four bags are unreliable.

Assessment of insect damage on samples of cocoa beans taken fortnightly by spear-sampling showed an increase from 0·20 per cent, insect-defective beans in November to 1·0–1·9 per cent, in June. Of 21,000 beans examined in April and May, L. serricorne occurred in 0·17 per cent., and 0·6 per cent, contained living insects. Damage by insects affecting more than 2 per cent, of the beans has been very uncommon in Ghana in the past few years. The effect on quality, as assessed by commercial grading and considered financially, is at present slight, as it also is in terms of loss of weight over the whole crop (certainly less than 0·1 per cent.). E. cautella is the most important species economically, because it can infest the premises of cocoa and chocolate manufacturers in importing countries, and spread to finished confectionery. It affects a large portion of the crop in significant numbers.

The primary infestation of cocoa before it comes into licensed storage occurs in thousands of small farms and villages, and no one district or type of source is of special importance. Increase of the infestation during storage occurs chiefly as a development of this primary infestation; cross-infestation from outside sources is relatively unimportant.

The application of synergised pyrethrin in white oil within storage sheds as a fog, from which a film was deposited on the stacked bags of cocoa, was carried out in many sheds at intervals of 3–4 days, and a comparison made between sprayed and unsprayed sheds, based on data from sieving. Spraying did not substantially reduce the development of infestations of L. serricorne or other beetles, nor was E. cautella controlled to a degree comparable with experience of similar treatment against E. elutella (Hb.) in Britain; this may be due to the fact that E. cautella in Ghana develops in bags throughout the stack, and not chiefly in the peripheral bags, as does E. elutella in Britain.

Conditions affecting the film-spraying of bagged cocoa in Ghana differ greatly from those in Britain. Uncontrolled ventilation at the eaves of sheds results in a considerable loss of insecticidal fog, and uneven distribution of deposit; the undersurface of the stacks cannot be sprayed, because they rest on wooden dunnage; it is difficult to maintain an effective oil-film on the topmost horizontal surfaces of the stack, near the roof, of which the temperature frequently exceeds 100°F.; deposits probably do not retain their toxicity for more than a few days.

Variations in the materials from which cocoa-storage sheds are constructed, and in their design, cause relatively small differences in internal climatic conditions, and these have even less effect on the temperature of the cocoa in bags, which is generally in the range 82–88°F. The moisture content of the cocoa was about one per cent, less in a hotter type of shed than it was in one of a cooler type, and it is considered that the construction of sheds should aim at producing the hotter, drier conditions that are attainable, in order to keep moisture contents down and restrict the development of moulds, mould-feeding beetles and Araecerus fasciculatus.

In vitro rearing of honey bee larvae is ideal for bioassay studies; no honey bee stable cell lines are available. Inconsistency of internal development staging of reared larvae and a susceptibility to contamination are common problems encountered. Standardized protocols on rearing larvae in vitro to make the larvae growth and development more similar to that of natural colonies are necessary to ensure the accuracy of experimental results and promote honey bee research as a model organism. Here, we concluded that when larval fasting weight was >160 mg, the time point of gut emptying can be defined as the critical point separating the larval and prepupal stages. In this way, we can conduct precise studies on the prepupal stage, such as organ remodeling during metamorphosis. Simultaneously, we further verified that recombinant AccApidaecin in genetic engineered bacteria added to the larval diet upregulated antibacterial peptide gene expression, and did not stimulate the stress response in larvae, nor did it affect the pupation rate or eclosion rate. This demonstrated that feeding recombinant AccApidaecin can enhance the individual antibacterial ability at the molecular level.