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.

Knowledge of the breeding habits of the Anopheline mosquitos has advanced greatly since the days when it was considered that the larvae of any species were distributed indiscriminately in all and sundry collections of stagnant water. In the Federated Malay States entomological research, which has now extended over many years, tends to show that preferences by the various species for different kinds of breeding-places exist; and attempts have been made to define in relation to particular species, or groups of species, or groups of species, the types of breeding-place favoured.

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.

As a general rule, on the Benue River and its tributaries, at least between Abinsi and Lau, the tsetses found are Glossina tachinoides and G. palpalis, the latter occurring far less frequently.

Male mating success depends on various traits and factors, and correctly identifying these traits can be key in the context of pest management. For tephritid pests, controlled through the sterile insect technique (SIT) traits, such as male size, can be manipulated through mass-rearing procedures. Thus, it is particularly important to understand whether male size can favor mating success. Here, we evaluated mating success of males of different sizes in Anastrepha ludens and Anastrepha obliqua, two species controlled through SIT. For both species, a morphometric analysis was performed of mated and unmated mass-reared and wild males in field cages. In both A. ludens and A. obliqua, wild females did not discriminate their mates based on male size and mated more frequently with wild males regardless of size. For mass-reared males, we found no evidence of an advantage of the large males compared to small males in mating success. However, we did find differences between the morphometric traits of mass-reared and wild males. In A. ludens, traits associated to mating success were Face Width (FW), Head Width (HW), Thorax Length (TL) and Wing Length (WL), and for A. obliqua were FW, HW, WL and WW (Wing Width). Overall, FW and TL were more consistent predictors of mating success. In conclusion, female choice seems to suggest multivariate selection, confirming that overall body size (expressed as pupal diameter, which is highly correlated with weight) is not a decisive factor in male mating success in these two species. However, morphological traits such as FW, HW, TL, WL and WW may be relevant in mating preference of wild female.

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.

Psyllaephagus yaseenisp.n. is described from Mexico, Central America and the Caribbean as a parsitoid of the nymphs of Heteropsylla cubana Crawford. The psyllid is a serious pest of Leucaena leucocephala, a shade tree and animal fodder in the tropics.

The first puparium of Glossina morsitans found in nature, as mentioned in Mr. E. E. Austen's recently published “Handbook of the Tsetse-Flies,” was taken in November, 1910, from the collection of mould and humus between the roots of a large tree (Ficus sp.) near the Gorai river below the Escarpment in the Lomagundi District, Southern Rhodesia. The tree is situated about 60 to 70 yards from the actual bank of the river, as it runs at present. It is in reality growing on what was the old bank of the river, which is changing its bed gradually owing to the soft nature of the ground through which it flows. At the time of the visit “fly” was abundant in the shade of the trees bordering the river, the sandy bed of which then contained no water on the surface, the nearest open water being twelve to fifteen miles away in the Hunyani river. It was thought at the time that this was the only pupa-case secured, and a search all along the river bank produced no others. A number of empty pupa-cases of other Diptera and Lepidoptera were, however, placed in a corked phial and labelled, and on going over these later in the laboratory, the anal end of a second tsetse pupa-case was found amongst them, showing the characteristic protuberances. This spot was again visited in April, 1911, and under the same tree five more empty puparia were found, but, as before, the most diligent search elsewhere failed to produce any more. A photograph of the tree taken in November is reproduced (Pl. XVII, fig. 2).

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.

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.

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.

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 sensitivity of males and females of Glossina morsitans morsitans Westwood to the vapour phase of bisazir was tested in the laboratory in a moving air stream at temperatures ranging from 12 to 20°C. Similar tests were conducted in still air in closed systems. Bisazir was used in its granular form or absorbed onto silicone rubber or cellulose fibre surfaces from solution in dichloromethane. As a crystalline solid, it lost only 5% of its weight in a moving air stream over 12 days. However, even in relatively still air, bisazir absorbed onto cellulose fibre discs lost 70% of its weight at 20°C and 80% at 30°C in 24 days. Estimations of the amounts of bisazir present on a surface by weight difference were higher than those estimated by gas chromatographic analysis. Hence, in addition to being volatile, bisazir must be regarded as somewhat unstable. Nevertheless, sufficient active ingredient remained over a long enough period for it to be considered as a practical means of sterilizing tsetse in the field. Females were found more sensitive to bisazir than males, but exposure times required to produce total sterility in both sexes did not affect survival. Exposure times of only a few minutes were sufficient to induce a significant reduction in female fecundity or male fertility at 30–35°C, temperatures which might be expected under field conditions in a device to sterilize automatically tsetse attracted to traps in the field. The degree of sterility induced was permanent, and at these short exposure times the temperature had no effect on female fecundity.

In studies in southern England in 1967–77, the numbers of Lonchoptera lutea Panz. in cereal crops, such as winter wheat, fluctuated from year to year, depending on an adequate supply of food, provided by decaying litter, for the larvae and on sufficient rainfall to keep the soil surface moist during May and June. Much sunshine was unsuitable for larval growth. The larvae fed mainly on fungal spores and were able to breed in wheat litter in the laboratory. In years when many crop plants were attacked by shoot borers such as Delia coarctata (Fall.) and Oscinelta frit (L.), L. lutea was more numerous than when there were few. Although in most years more males than females appeared in emergence traps, more females than males were caught by sweeping and in light- and suction traps.

In February, 1944, No. 2 Entomological Field Unit, R.A.M.C., arrived in India with the first consignment of DDT (dichlor-diphenyl-trichlorethane) to be used there for research purpose. Experimemts to determine the larvicidal effects of this substance were carried out by the unit, of which I was Commanding Officer.

The efficiencies of people sampling cabbage plants in the field for total numbers of Myzus persicae (Sulzer) were found to differ. Significantly more aphids were counted on leaves taken to the laboratory than on leaves examined by inexperienced people in the field, but field counts by an experienced person did not differ significantly from the laboratory sample. The implications of differences between people and the possibility of correcting for them in surveys are discussed.

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.

DDT (p,p'-dichlordiphenyl-trichlormethyl-methane) has been shown to be very toxic to the housefly, Musca domestica, L., when applied as a spray containing 0·1 per cent, w/v or more in kerosene. DDT at 1 per cent, gives an effective spray for practical use, but at lower concentrations the speed of knock-down is too slow. This disadvantage can be overcome by the admixture of a small amount of pyrethrum. A mixture of 0·03 per cent, w/v total pyrethrins and 0·1 per cent, w/v DDT in kerosene is recommended as a suitable fly spray for practical use. This mixture can be stored in glass bottles in the dark for at least 17 months at 27·5° C. without marked deterioration. Its toxicity may be increased by the incorporation of a suitable activator, e.g., sesame oil or isobutylundecylenamide.

The impurities in crude preparations of DDT appear to exert no toxic effect on houseflies.

DDT acts more slowly when dissolved in industrial methylated spirit than in kerosene.

Attention is drawn to the residual film effect of DDT on walls, etc., and an example is given to show how this effect was employed in the control of a fly population in a kitchen.

The symptoms of poisoning of flies by DDT are compared with those caused by pyrethrum. DDT is relatively slow in action; it is a severe irritant, causing the flies to buzz violently at one stage; it induces marked tremors during the coma preceding death; and, at death, it causes the legs to be tightly flexed at the femoro-tibial joint. When the pyrethrins and DDT are mixed in a spray, these constituents, so far as can be judged from the train of toxic symptoms, act independently, so that the rapid paralytic effect of the pyrethrins keeps the insects immobile until the slow lethal effect of the DDT supervenes.

This work has been carried out as part of the programme of research of the Pest Infestation Laboratory, and this account is published by permission of the Department of Scientific and Industrial Research.

This part of the study of the garden chafer, Phyllopertha horticola (L.), in the English Lake District covers the flight seasons 1948–1952. Annual sex ratios in the population of pupae (just before ecdysis to adult) ranged from 34·6 to 46·9 per cent. females.

The flight season begins with the emergence of some adult males upon the sward. If the weather continues favourable, the earliest females appear on the second or third day of the season. Unsuitable weather delayed the advent of females until the sixth day in two seasons. In a homogeneous population, primary emergence is complete in just under a fortnight, at the end of which time numbers of beetles seen on the grass sward are at their peak. Phase 1, swarming over the sward, continues, with dwindling numbers, for just over a week more (overlapping Phase 2, swarming on the bracken).

The female/male ratio rises throughout Phase 1 except for a tendency to fall in the last day or two. But generally for most and sometimes the whole of Phase 1, the proportion of females above ground is far below the true population ratio. This is partly because population emergence in the female is 1–2 days behind emergence in the male; but much more because after primary emergence the male is fully involved in above-ground activity every day until the beginning of Phase 2 or end of Phase 1 (depending on whether he emerges earlier or later), while the female is not.

In the same way, there are no females present on the bracken until after the first day of Phase 2, but the proportion of females rises more quickly and to a higher level than in Phase 1. By the middle of Phase 2, the proportion is close to the true population ratio. Since males are now confined to the bracken, this means that mass oviposition is more or less complete. During the last week of the season the female proportion rises steeply. This is because females live a few days longer than males besides being 1–2 days behind males in their original emergence.

After primary emergence, the average female lives about a fortnight, the male rather less. Approximately the first half of adult life is spent in the grass sward area, the second half on the surrounding bracken (or hedges or trees).

As Phase 1 proceeds, the pairing rate of females decreases. This is partly because the proportion of males is falling and therefore fewer males are available to search for each female over the grass sward, and partly because of a change in mating behaviour of the female as she ages. On the other hand, pairing rate is at its highest (average 82%, maximum 95%, of available females) in Phase 2 when the proportion of males is at its minimum (actually the true proportion in the population). This is because on the bracken the beetles are confined to a much smaller area than on the grass and therefore males find females more readily.

In flying weather, the proportion of beetles in the air at any moment is at best no more than about 70 per cent.; usually it is less than 50 per cent. On the whole males are very much more given to flying than females.

♂. Black ; flagellum brownish red, hind legs from the femora to the claws blackish red ; scape, fore and middle legs, hind trochanters and hind trochantines, light testaceous red ; palpi almost white ; basal ventrites whitish ; stigma and wing veins brown.

♂. Head rugose throughout, except that the occiput is rugoso-reticulate and that the vertex between the ocelli and the toruli is rugoso-striate ; face with indications of a median keel ; antennae moderately thick and strong ; basal joint of flagellum a little longer than twice its breadth, about 0·24 mm. long ; clypeus apparently emarginate, just about half as long as distance between facial depressions, which latter are nearer to the eyes than to the apex of the clypeus ; posterior ocelli nearer to the eyes than to each other. Thorax : mesonotum closely and strongly punctate, anteriorly almost rugose, as are also the mesopleurae except for a posterior median smooth and shining area ; mesopleural sulcus apparently smooth ; scutellum apparently rugose ; metanotum apparently not crenulate ; propodeon with an extremely short median longitudinal carina which, bifurcating at its apex, emits two strong carinae which, on each side, run transversely across the basal half of the propodeon and join a strong carina which in conjunction with a strong lateral longitudinal carina encircles the spiracles, as in M. kuchingensis ; remainder of the propodeon apparently rugose between broad reticulations, except outside the lateral keels, where it is only rugose.