The map of South America shows Peru as a rather long, narrow country, broadening at the north, and presumably tropical in climate judging by its position just south of the Equator, but with high mountains close to the coast. But it does not show the cold ocean current coming from the south—the Humboldt Current—or ar least we are not accustomed to noticing such presumably minor features, even though in the case of Peru, this is equal in importance with the mountains in determining the climate of the country and every factor that the climate may affect.

Attempts were made to find alternative, less persistent, toxicants to aldrin for use in baits against Anoplolepis longipes (Jerd.) in the Seychelles. More than twenty toxicants were tested (some in more than one formulation) for effectiveness as poisons and for repellency to ants at the concentrations used in baits. None was as effective as aldrin, but certain formulations of pirimiphos-ethyl, pirimiphos-methyl and mecarbam were promising because they gave good kill of ants in the laboratory and were of relatively low repellency and therefore acceptable in bait formulations.

The species commonly known in the West Indies as the pepper flower-bud moth has been shown not to be Gnorimoschema gudmannella (Wlsm.), as hitherto supposed, but an undescribed species, for which the name Gnorimoschema capsica is proposed. The species is described and differentiated from G. gudmannella and other species in the Grnorimoschemini.

Exitianus curvipenis (representing a new sixth species-group) from rice-field grasses in Nigeria, and E. upenis (okahandia-group) from open grassland in Abyssinia are described as new.

A breeding-place of Glossina pallidipes Aust., in evergreen shrubs of Craibia sp. on the Kiangine river, Makueni, Kenya, was studied by means of hand-searching for puparia in conjunction with records of rainfall and temperature. A fly-patrol was also operated. The country away from the river was thorn-scrub, with Acacia and Commiphora trees predominating.

Three sites, each of 200 sq. yards, divided into 50 squares, were marked out, and two of them were searched monthly and the third quarterly.

Site “ A ” was searched nearly every month between April 1949 and June 1952, and full puparia were nearly always found. Numbers varied very widely; and it was noted that few could be found in rainy seasons during the months of November to January and April to May, though 1950 was an abnormal year. A consistently large increase in numbers was observed in February, the hottest and driest month, and a rather less marked increase towards the end of the long dry season in September and October. Large numbers of full puparia also tended to coincide with times of low average minimum temperature.

The numbers of flies caught on the fly-patrol did not appear to bear any close relation to the numbers of full puparia discovered.

Testing for efficiency of searching by means of marked puparia showed that about 40 per cent. of puparia were recovered, so that results must be taken as relative.

Cacoecia histrionana Froel. a European relative of the North American spruce budworm, Choristoneura fumiferana Clem., was found in several localities on the north-eastern frontier of Bavaria in 1949, but was not abundant anywhere.

Details are given of its biology based upon observations made during large-scale collecting in the summer of 1949, which yielded approximately 2,100 larvae of C. histrionana.

An important characteristic of the species is the great variation in the stages of larval development present at any given time, which is apparently caused chiefly by the absence of diapause as a synchronising factor.

Approximately 4°C. was found to be the lower temperature limit for movement and feeding of larvae ready for overwintering.

Three samples of larvae taken in favourable localities showed that 0-15 to 0-70 larvae were present per metre length of spruce forest edge from ground level to a height of 2 metres. An estimate of the minimum population is made for a limited and well searched area.

From 1803 C. histrionana larvae collected in the field, 15 species of primary parasites and four of hyperparasites were bred. Combining the result of three samples taken at different times the minimum reduction of the population after hibernation is calculated to be 66-8 per cent., the parasitism of pupae at least 13-5 per cent. Egg parasitism occurred.

Nine of the 20 parasites, known hitherto from C. histrionana, have been bred from other hosts of the same animal community.

The most important larval parasite was Meteorus ruficeps Nees which completes 2-3 generations in one generation of C. histrionana. A proportion of the population also overwinters in other Microlepidoptera, concentrating on C. histrionana in summer. Details of its life-history are given.

Occasionally some larvae were found that had probably died from disease but disease, as a mortality factor, was of little consequence in the observation area in 1949.

Mortality caused by parasites proved to be very important in affecting changes in the population density. This result does not agree with Eidmann's theory that the scarcity of C. histrionana is due to climatic control.

A recent study on ladybird, Menochilus sexmaculatus (Fabricius) demonstrates that males perform post-copulatory mate guarding in the form of prolonged mating durations. We investigated whether food resource fluctuation affects pre- and post-copulatory behaviour of M. sexmaculatus. It has not been studied before in ladybirds. For this, adults were subjected to prey resource fluctuations sequentially at three levels: post-emergence (Poe; 10 days), pre-mating (Prm; 24 h) and post-mating (Pom; 5 days; only female). The food resource conditions at each level could be any one of scarce, optimal or abundant. Pre-copulatory and post-copulatory behaviour, and reproductive output were assessed. Post-emergence and pre-mating nutrient conditions significantly influenced the pre-copulatory behaviour. Males reared on scarce post-emergence conditions were found to require significantly higher number of mating attempts to establish mating unlike males in the other two food conditions. Under scarce post-emergence and pre-mating conditions, time to commencement of mating and latent period were high but opposite result was obtained for mate-guarding duration. Fecundity and per cent egg viability were more influenced by post-mating conditions, with scarce conditions stopping oviposition regardless of pre-mating and post-emergence conditions. Present results indicate that pre- and post-copulatory behaviour of ladybird is plastic in nature in response to food resource fluctuations.

♂ (Type). Antennae somewhat longer than the head and pronotum together. Frontal ridge flat, punctured, gradually narrowed to the apex, its margins obtuse. Fastigium of the vertex slightly concave, oval, with rounded apex and almost smoothed lateral carinulae. Occiput with a scarcely distinguishable median carinula.

A new method of determining the duration of the aquatic stages of Anophelines in nature is described. Repeated daily dippings of a stretch of stream were made, and the numbers of pupae and of larvae of each instar were recorded. The duration of the aquatic stages was then determined by analysis of the sequences of peaks in these numbers.

The duration of larval life of A. minimus, when living in a stream at an average daily range of water temperature between 26·5°C. and 30·6°C, was seven days.

The full life cycle of A. minimus, under monsoon conditions in Assam, probably occupied 14 days—egg 2 days, larva 7 days, pupa 2 days, adult to first egg-laying 3 days.

Medical Officers and others interested in tropical sanitation often find great difficulty in rapidly identifying adult mosquitos. Four Anophelines have been found in the Zanzibar Protectorate, two of these being well-known malaria carriers. The identification of the two latter with the aid of a pocket lens is quite simple.

There are in the Sudan three species of migratory locusts : Anacridium moestum melanorhodon, Walk., or the tree locust, Locusta migratoria, L., and Schistocerca gregaria, Forsk., sometimes termed the desert locust. Of these the last-named is the plague locust of the country—the other two species being relatively unimportant—and is the species referred to as the “ locust ” throughout this paper.

From 1899 till 1917 swarms of locusts occurred annually, but then followed a period of ten years during which the Sudan suffered no damage from this pest. In 1927 and again in the succeeding year the locust reappeared as a plague, and there is little doubt but that it is to be expected year by year over an extended period and until the cycle either naturally terminates or is artificially brought to an end. The swarms of fliers appear from May onwards and oviposit in July and August when and where in the arid regions sufficient rain has fallen, the resulting generation of adults emigrating in October. A certain amount of breeding takes place during the winter on the Red Sea littoral, where winter rains occur, but this district is relatively small and easily dealt with ; the main problem is how to prevent breeding during the summer rainy season throughout the vast areas of the central and northern Sudan.

Anjeerodiplosis peshawarensis Mani is a serious pest in North India of the fruit of the country fig (Ficus carica), which is its only known host. The midges are abundant, hovering under the host tree in the mornings and at dusk, and breed throughout the year, except in the summer from April until the July rains. In this period newly formed fruits are not infested, but in other months scarcely 30 per cent, of the fruits remain free from attack.

Eggs are laid in fruits when they one week old, succulent, and of the size of a pea. The eggs are minute, hyaline, unsculptured, oval and pedicellate and occur in bundles of 16. Incubation takes three days in September and March and five days in December and January. In laboratory tests, average viability in January was found to be about 83 per cent.

The entire larval period is passed inside the figs, each of which may contain 200–300 larvae. There are four larval instars, which differ in size according to Dyar's law and in morphology. The first-instar larva is devoid of cuticular outgrowths and does not show spiracles; the second and third instars have nine pairs of spiracles and possess characteristic spines, warts and tubercles; the fourth instar develops the sternal spatula. The entire larval period lasts three weeks from the middle of August to October and four weeks in January and February. From the middle of April until the July rains, fourth-instar larvae remain inside the figs. When the larval period is three weeks, the first and second instars together and the third and fourth instars separately last about a week.

Full-grown fourth-instar larvae bore out of the fruit and drop to the ground, where they jump for some time with the aid of their sternal spatula. They finally pupate in the soil without forming a cocoon but become covered in a protective case composed of soil particles that adhere to the larval skin. Early fourth-instar larvae, which do not have a sternal spatula, if taken from the fruits, may also successfully pupate, and the pupal period is normal. This period is 10–15 days between July and November and 25–26 days in January and February. It is shortest (10 days) in the rainy season, when both temperature and humidity are high.

The pupa is obtect, creamy white and bears poorly developed cephalic horns and bristles, well developed thoracic horns and many spines and cuticular outgrowths. Mortality in the pupal stage is between 15 and 30 per cent.

Emergence of the adults invariably occurs in the early hours of the day. Two or three days before emergence, the protective case becomes detached piecemeal. Males emerge before females. The ratio of males to females on the day of emergence is 1:2 between March and December and 2:3 in January and February. Copulation starts soon after emergence and lasts from 60 to 90 seconds.

There is considerable overlapping of generations. On the basis of the time required for completion of the life-cycle in different months, it is calculated that seven generations are completed in a year.

Male.—General coloration fuscous, with the vertex of the head, pectus, underside of abdomen, anal region, legs and base of antennal shaft mouse-grey. Fore-wings, above, covered with mouse-grey scales, amongst which are scattered irregular patches of fuscous-black scales, these predominating but forming no definite pattern; beneath, covered more uniformly with fuscous-black scales, except in the region between the first anal vein and the inner margin, which is covered with narrow elongate oval mouse-grey scales. Hind-wings above and beneath covered with fuscous scales, the inner margin furnished with long fuscous hairs. Cilia of both wings fuscous-black.

Females of the white grub beetle, Dasylepida ishigakiensis, release both (R)- and (S)-2-butanol as sex pheromones, but the males are only attracted to (R)-2-butanol. In laboratory-reared females, the proportion of the (R)-isomer decreased significantly as their calling opportunities increased and as they aged. We examined whether such qualitative changes also occur in field populations. We collected virgin females from the field and then trapped and analysed the volatiles emitted during their first and second callings. The ratio of (R)- to (S)-2-butanol (R/S) was 78:22 at the first calling, but shifted to 39:61 at the second calling. While investigating the composition of the female pheromones, the question arose as to whether the male preferences change in response to the shift in female pheromone composition. To answer this question, we observed the behaviour of young and old males in response to various R/S ratios as lures in the laboratory and in the field. In the flight tunnel assay of laboratory-reared individuals, young males touched female models with a 9:1 R/S ratio lure less than those with pure (R)-2-butanol; however, older males touched the two groups with equivalent frequency. In the field trap test, older males were much more attracted to (R)-2-butanol-scented lures. When we tested using lures with the same amount of (R)-2-butanol but added different amounts of the (S)-isomer, we found that increased levels of (S)-2-butanol resulted in lower attractiveness to males. (S)-2-butanol was confirmed to have an inhibitive activity in the attractiveness of (R)-2-butanol.