The water loss and mortality of Calandra granaria (L.) and C. oryzae (L.) have been studied at low pressures in controlled humidities. The mortality of both species is closely associated with the loss of water under these conditions, a loss which is prevented by a high humidity in the surrounding air. C. oryzae is consistently more susceptible than C. granaria. Substantially linear relations were observed between water loss and decreasing relative humidity (range 0–85%), increasing period of exposure (range 4–16 hr.), and decreasing pressure (range 2–8 cm. mercury). At lower pressures (3–4 mm. mercury), the Water loss and mortality of both species were greatly reduced, suggesting that some physical change had occurred in the insects. A covariance analysis of the mortality response, using the loss of water as a concomitant variate, showed that there was no significant part of the mortality that was not accounted for by the water loss from the insects.

The distribution in Britain of carrion-attracted Calliphorinae was examined by simultaneous trappings, under standard conditions, at 51 stations so distributed as to be more or less representative of the country.

From published records and other sources, the known distribution of each species by vice-counties was delimited and compared with the observed results.

Lucilia sericata (Mg.), L. caesar (L.), Calliphora erythrocephala (Mg.) and C. vomitoria (L.) are generally distributed. L. illustris (Mg.) is more widely distributed than was recognised, and is probably general, though relatively uncommon in hill country. Phormia terraenovae R.-D. and Cynomyia, mortuorum (L.) are also general, though more common in the north. The decrease in frequency southwards is more pronounced with C. mortuorum. and both species occur only rarely in Wales. L. silvarum (Mg.), believed previously to be confined to England, is also possibly generally distributed; it was trapped as far north as Caithness. It is uncommon north of the Highland Line.

Lucilia ampullacea Villen., for which known records are restricted to south of the Humber-Mersey line, appears similarly to be almost general; it was taken both in hill and plains country up to the Inverness region.

Of the remaining species that show some degree of geographical limitation, Acrophaga subalpina (Ringdahl) is the most widely distributed. It occurs at least as far north as the Inverness region, and south to the Severn-Wash line.

The only Lucilia species with clearly restricted distribution is L. richardsi Collin. Its known territory was England south of the Pennines; this has now been extended into Wales and north to Cumberland and Durham, with one isolated record for the north-east of Scotland.

Calliphora loewi End., believed a northern species, was taken throughout Scotland and northern England. C. uralensis Villen. is restricted to the northwest, and the Western Isles.

Brief notes are given of the habitat preferences and seasonal distribution of the species.

A new genus, Austrotortrix, is erected for Teras postvittana Walker, the Apple Leaf Roller or Light Brown Apple Moth, a common pest of apple and Citrus in the coastal regions of Australia, and in Tasmania and New Zealand.

Two new synonyms of A. postvittana in addition to those already recorded are given.

As there are several species in Australia closely resembling postvittana, making identification difficult, descriptions of the genitalia of postvittana are given as these provide the best means of positive identification.

Apart from the type species, postvittana, ten other species are assigned to the new genus.

The principal pest of sugar-cane in northern Tanganyika is the Red Cane Beetle, Cochliotis melolonthoides (Gerst.) (Melolonthidae). Descriptions of adults and larvae of Cochliotis and of allied beetles found in the same area are given.

The bionomics of Cochliotis have been studied in the field over two seasons. The life-cycle is annual with adult swarming in early October and a season of maximum larval damage in July–August.

The intensity of infestation and the nature of the losses are discussed, and the mortality factors which act upon Cochliotis in nature are reviewed.

Cultural control measures suggested include the deferment of planting until July to October, when larval activity has waned; introduction of quick-maturing varieties, mechanically cultivated so that long ratooning can be gradually eliminated; regulation of the water table by control of irrigation, and the trial of resistant varieties. The Mauritius varieties M. 134/32 and M. 165/38 are suggested in this connection.

Biological control is discussed and a review of the parasite species that might possibly be introduced is made largely from the writer's Mauritius work on Clemora smithi (Arr.).

Experiments in the chemical control of Cochliotis are described and the final recommendation is the application at planting of ½ lb. per 50 ft. of furrow of a BHC powder containing 2·5 per cent, of γ BHC. This practice has been adopted by the infested estate with successful results in virgins and first ratoons.

Further work is suggested on the chemical protection of second and later ratoons by surface application of BHC or aldrin.

A simple method for culturing Culicoides nubeculosus (Mg.) in the laboratory is described, the medium used for rearing the larvae being a mixture of powdered mud from near a farm byre, dried autolyzed yeast and powdered charcoal, in the proportions 25:3:2. A layer of the mixture 4 mm. deep was spread over the bottom of unglazed earthenware pots, 6 in. diam. x 1 in. high, and just covered with water. After about three weeks in an insect-proof cage in the open, the pots were brought into the laboratory, the temperature of which was maintained at 20°C. except for brief periods in very hot or very cold weather. Each pot was stocked with from 70 to 220 newly hatched larvae, derived from a single batch of eggs laid on moist filter-paper discs in 3 x 1-inch glass mating tubes by adults that had been fed on human blood and provided with raisins. The surface of the medium became covered with a growth of bacteria, algae, fungi, and protozoa, which provided a source of food for the larvae. These made shallow burrows in the substratum from which they partially emerged to feed and in which they pupated. About 45 per cent, of those introduced emerged successfully as adults.

The incubation and pupal periods lasted 3–6 and about 4–7 days, respectively. The time taken for larval development varied greatly between individuals from the same batch of eggs, and also between batches started at different times of year. The complete life-cycle of examples started as larvae in January–September was thus 3–8½ weeks, the period over which emergence occurred amongst a single batch being 1–5 weeks; the corresponding figures for those started as larvae in October were 6–18 and 2 to nearly 12 weeks.

The behaviour in the various stages is briefly described.

Records are given of the localities (with altitudes) of approximately 900 specimens representing 21 species of Diatraea Guild, and four species of Zeadiatraea Box, from Mexico, Central and South America. Most of the moths were reared from known food-plants (all Gramineae) and the larvae of several of them are important agricultural pests as stalk-borers in sugar-cane and maize.

Three species of Diatraea are described as new to science and their genitalia are figured, viz., colombiana, sp.n. (Colombia), balboana, sp.n. (Panama) and veracruzana, sp.n. (Mexico). The previously unknown male of D. instructella Dyar (Mexico) is described and its genitalia figured. These moths (except colombiana) are illustrated in the Plate. An attempt is made to clarify the confusion which has existed concerning D. magnifactella Dyar and the closely related D. considerata Heinrich, both of which are endemic in Mexico, but each with its own area of distribution without overlapping. The paper includes additional records and observations on the polytypic D. busckella Dyar & Heinrich and certain of its subspecies in Panama and Venezuela, previously discussed by the writer in this journal in 1951.

Insects and mites collected within the various sections of a combined flour, oatmeal and provender mill are listed. The mill in question is one of the most northerly in Britain. Notes are given on the distribution, abundance and associations, within the mill, of the species recorded. The economic importance of those considered to be pests is assessed.

The three most important pests were found to be Ephestia kuehniella Zell., Gnathocerus cornutus (F.) and Tribolium confusum Duv. It is suggested that Endrosis sarcitrella (L.), Tipnus unicolor (Pill. & Mitt.) and Cryptophagus cellaris (Scop.) might be included in the list of “ hardy ” insects given by Solomon & Adamson (1955) in their paper on the powers of survival of storage and domestic pests under winter conditions in Britain.

Investigations on the Akah river, in the 4th Division of Sarawak, showed 13 species and one variety of Anopheles to be present. A. l. leucosphyrus Dön., the principal malaria vector, was the only species common in houses.

A. l. leucosphyrus has a strong preference for human blood and feeds throughout the night, with a peak of activity soon after midnight. Both fed and unfed mosquitos rest indoors on the walls but the latter become increasingly scarcer later in the night. Most individuals rest low down (62% below 3 ft., 96% below 5 ft.) but only a negligible percentage remains in the house after daybreak. Observations suggest that many females spend quite long periods resting outside the house before entering and that entry is almost entirely through windows and other openings in the walls; very few enter the space below the house. There is also evidence of two separate stimuli, or levels of activation, one bringing the mosquito to the bait and one initiating the act of feeding.

Wet weather was accompanied by an abrupt increase in catches of A. l. leucosphyrus and dry weather by a decrease—this is thought not to be due to any effect on breeding places. During the wet period, females entered earlier and tended to rest to a greater extent before feeding.

Ovipositing females of Nupserha bicolor Thoms, ssp. postbrunnea Breun. cause loss of stem length in jute, Corchorus olitorius, by girdling the stem above and below a slit in which the egg is laid. The slit is made by two successive indentations of the mandibles. It is composed of a central pit and two lateral punctures. Girdling is restricted to that portion of the stem which falls within the stem-diameter range of 0·2 cm. to 0·4 cm.

A relationship exists between the length of the mandibles of the female, the depth of the stem tissue from the epidermis down to the periphery of the pith (extra-medullary tissue), and girdling and oviposition.

For girdling, the optimum ratio between the mandibular length and the depth of extra-medullary tissue as measured from the epidermal furrow and ridge of the stem (pentagonal in this region) is 1:0·80 and 1:0·99, respectively. Frequency of girdling gradually decreases in those regions of stem where the depth of extra-medullary tissue increases or decreases these ratios.

Mosquito larvae derived from eggs laid in earthenware pots in various habitats on the site of University College, Ibadan, in Nigeria were collected over a period of 26 months.

Anopheles gambiae Giles, Aëdes aegypti (L.) and Culex (Lutzia) tigripes Grp. were the species most frequently collected.

The relation of these results to the fluctuation in the populations of the species concerned is discussed. It seems unlikely that pot collections give results which can be directly related to the numbers of mosquitos in the field, but they can elucidate questions of mosquito biology and behaviour.

The present list of the mosquitos of south Thailand makes certain corrections to a list previously published and adds Anopheles barbumbrosus Strickl. & Chowd. and Anopheles letifer Sandosham to the list.

Taxonomic notes are given on eight species and a description of the larva of Uranotaenia bimaculiala Leic., previously undescribed, is included. The characters by which U. bimaculiala can be separated from the closely allied U. micans Leic. and U. edwardsi Barraud are detailed.

The persistence and toxicity to Tribolium castaneum (Hbst.) of initial deposits approximating to 10, 20 and 40 mg. per sq. ft. of γBHC were studied over a period of three weeks in a typical warehouse in Kano, Northern Nigeria. Chemical and biological assessments indicated that the lowest rate of application was inadequate for practical insect control whilst the other two rates showed very similar biological activity up to eight days after treatment. Thereafter small quantities persisted from applications at the highest rate for a further week but the resultant mortalities were inadequate for purposes of field control. It was concluded that to maintain control of T. castaneum, weekly applications of BHC would be required and that the rate of application should approximate to 20 mg. per sq. ft.

Mealybug populations (Pseudococcus njalensis Laing) originally present in piles of slash infected with the virus of swollen shoot of cacao are usually small. It is suggested that many of the insects leave the trees at an early stage in the development of infection.

Slash piles offer conditions which induce mealybugs to remain within them. The piling of infected slash retards the rate of wilting of the cut wood and consequently retards the rate of migration of the mealybug population. The construction of piles protects the mealybugs from direct insolation and rainfall and leads to the persistence of the population on the cut wood. The colonies which survive the longest are those in the lower part of the heaps where death and desiccation of the material is most delayed.

Mealybugs continue to live and to reproduce within heaps of slash for as long as nine weeks or more. Reproduction of the mealybugs is stimulated as the tissues of the felled trees become wilted and the resulting first-instar nymphs contribute numerous participants to such migration as does occur. There is evidence from laboratory experiments that these insects are not potential vectors.

The concentrating of mealybugs in slash piles produces no increase in the population of Coccinellid or Cecidomyiid larvae within the piles.

Mealybugs are capable of walking quite rapidly for long distances over smooth surfaces. They become incapable of movement when starved for a few days and the majority die within a week. A soil surface seriously impedes the progress of mealybugs which leave the slash heaps and this effect is more marked with the nymphal stages. Even on clean-weeded soil the rate of travel is slow and few. if any, insects can travel over appreciable distances in the period during which the virus may persist within them. Results of preliminary experiments were confirmed by the use of insects labelled with radioactive phosphorus.

Some of the ants, which become associated with slash piles and which remain in attendance of the residual mealybug population, carry mealybugs, but the number of insects transported in this way is of little practical significance.

The establishment of migrating mealybugs on seedlings and mature cacao is poor even in the presence of their attendant ants.

All these factors make the possibility of infecting healthy trees from infected slash extremely remote. There is accordingly no reason to believe that the efficiency of “ cutting out ” is seriously reduced by the movement of vectors from the infected trees which are cut out.

Without the co-operation of farmers in supporting the removal of contact trees no further recommendations can be advanced to improve the present method of control of swollen shoot.

The effects of cultivation and treatments with DDT and BHC on soil Collembola and Acarina were, investigated. Cultivation resulted initially in a drastic reduction of the micro-arthropod population and in the fallow plots this reduction persisted. Re-seeding resulted in rapid recolonisation by Collembola, but the populations of Oribatei and Mesostigmata remained at a low level over a period of 17 months after sowing. Treatment with BHC caused a heavy reduction of most micro-arthropoda. DDT caused reductions of mites, particularly Mesostigmata, but there was a marked increase of Collembola in the plots so treated. Significant increases of Collembola and significant reductions of predacious Mesostigmata were also noted in the comparison of plots treated with a DDT plus BHC mixture with those receiving BHC alone. The increase of Collembola was thus associated with a reduction of predatory pressure. In most cases, the effects of the treatments that included BHC were apparent 17 months later, but a temporary recovery of near-surface dwelling Collembola occurred in the BHC-treated plots in February 1952. Of the groups and species significantly affected by insecticide treatments in October 1951, only in one case did the data of October 1952 produce significant evidence of recolonisation. This recovery was noted in the DDT-treated population of Punctoribates punctum (Koch).

Tinea pellionella (L.), commonly known as the Case-bearing Clothes Moth or Fur Moth, is of world-wide distribution and is of considerable economic importance. It has been recorded on a variety of substances, particularly those of a keratinous nature. In India, it has been found as an important pest of woollen textiles. Its life-history and habits have been systematically investigated at different levels of temperature and humidity.

The incubation period is 4 to 5, 5, 6 to 7 and 6 to 7 days at 21·5, 25, 30 and 32·5°C., respectively. Temperatures higher than 32·5°C. have been found lethal to eggs. Humidity has no effect on the incubation period. Percentage viability of eggs is greater at lower than at higher temperatures.

Both temperature and humidity have been found to influence the larval development and the number of larval instars. Irrespective of temperature, higher humidities favour shorter larval development and the shortest larval period is at 25°C. and 90 per cent. R.H.

Woollen materials impregnated with yeast are more suited for the larval development than those not so treated. Larvae do not exhibit colour preference. Woollen fabrics dyed with Cloth fast orange G 4 per cent, manufactured by “ Ciba ”, however, inhibit the growth of freshly hatched larvae.

The behaviour of the larvae to direct sunlight has been studied. The rôle of (a) diffused light alternated with darkness, (b) darkness, (c) temperature and (d) humidity on the extent of damage caused by the larvae has been investigated. Under the conditions of the experiments, the amount of damage in continuous darkness was significantly greater than in alternating light and darkness, and that at 90 per cent. R.H. significantly greater than at 30 per cent., but there was no significant difference in the amount of damage at 27·5° and 32·5°C., respectively, and 90 per cent. R.H.

The mode of pupation has been described. The pupal period has been studied and found.to occupy 18 ± 0·4, 10·3 ± 0·16 and 10·3 ± 0·33 days at 21·5, 25 and 30°C. and 90 per cent. R.H., respectively. Humidity has no effect on this period.

The effect of temperature and humidity on (a) the preoviposition, oviposition and postoviposition periods and (b) number of eggs laid by a female has been studied. The life-span of the male and female, the relationship between the weight of the female at emergence and fecundity (which was highly significant) on the one hand and length of life (which was not significant) on the other has also been investigated. Sex ratio between females and males has been found to be 2·6:1. Three to four generations in a year have been recorded at 26 ± 8·0°C. and 82 ± 10 per cent. R.H. when the larvae are fed on woollen fabrics impregnated with yeast.

Literature, mainly Indian, pertaining to the recorded hosts of Bracon hebetor Say and B. brevicornis Wesm., and on the taxonomy of the two species, has been reviewed. Observations on different morphological characters, including the male and female genitalia, which have been used in establishing the identity of the two species, have been made. A large number of B. hebetor specimens reared in Bangalore on Corcyra cephalonica (Stnt.), Ephestia cautella (Wlk.), Adisura atkinsoni Moore and those collected in food-grain godowns, and of B. brevicornis reared on C. cephalonica and E. cautella in Bangalore, on Nephantis serinopa Meyr. from Coimbatore (South India), on Pyrausta nubilalis (Hb.) from Canada and on cotton bollworms (?) from Delhi (North India), have been examined.

Differences in colour, relative proportions of antennal joints and punctation on the abdomen have been found to be variable and as such are not to be depended upon for distinguishing the two species. The number of antennal joints which has hitherto been considered to be the decisive character by which the two species may be separated is also not reliable as there is a wide range of variation even in the progeny of a single pair of parents. Above all, the fact that the two species interbreed and give rise to fertile offspring, which also show a fairly wide range of variation in the number of antennal joints, proves that the two are identical, and there is no ground to treat them as two distinct species, at least so far as the Indian specimens are concerned, for which Bracon hebetor Say is the valid name.