Detailed taxonomic studies of adult Cecidomyiidae reared from inflorescences and seed-heads of species of Gramineae and Cyperaceae during field surveys in Queensland and the Northern Territory of Australia in 1970–73 established that Contarinia sorghicola (Coq.) is restricted to non-indigenous crop and weed species of Sorghum section Sorghum that have been introduced to Australia by man and that three morphologically distinct species of Contarinia occur on native Australian grass species of Sorghum section Parasorghum. An earlier report that the wild grasses Dichanthium, Bothriochloa and Eriochloa serve as alternative hosts of C. sorghicola was not confirmed by detailed examination of long series of specimens reared from these hosts, nor was the pest species found on any other genera of Gramineae. It is therefore concluded that, in Australia, C. sorghicola has been spread (probably in contaminated seed) and maintained by grain and forage sorghums and that wild grasses are not potential sources of crop infestation. Eleven new species are described: C. roperi sp. n. and C. plumosi sp. n. from Sorghum plumosum; C. intrans sp. n. from S. intrans and S. stipoideum; C. sehimae sp. n. from Sehima nervosum; C. bothriochloae sp. n. from B. bladhii; C. dichanthii from D. annulatum var. fecundum and D. tenuiculum and possibly from D. affine and D. sericeum; C. passlowi sp. n. from D. annulatum var. fecundum; C. alloteropsidis sp. n. from Alloteropsis semialata; C. brevipalpis sp. n. from Eragrostis brownii; C. scirpi sp. n. from Scirpus lacustris and C. fimbristylis sp. n. from Fimbristylis bisumbellata. Characters of the female cerci were especially useful in diagnosing species, making it easier to identify females than males. Cecidomyiids of the genus Geromyia were reared from Setaria and cecidomyiids of the genus Lasioptera were reared from ten grass genera and one sedge genus during the surveys, but this material is not dealt with in detail. The needs for further field work and taxonomic studies are stressed and it is suggested that apertures on the dorsal surface of abdominal segment VIII in female C. sorghicola may be the openings of sex pheromone glands and would merit further detailed investigation.

Five insecticides (Thiodah, Bromodan, dimethoate, Dipterex (trichlorphon) and Sumithion) were applied topically in solution to young adults of the tsetse fly Glossina morsitans Westw. The toxicity of Thiodan (LD50 for males, 0·0012 µg.; for females, 0·0014 µg.) lay between that of Telodrin and dieldrin, and that of Bromodan (LD50 for both sexes combined, 0·0032 µg.) between that of dieldrin and γ BHC. Dimethoate, Dipterex and Sumithion were all less toxic than Baytex, but were not fully evaluated.

Results recorded in this paper and earlier ones in this series, and those of workers using Musca domestica L., are discussed in an attempt to rationalise the search for new toxicants for tsetse flies. Chlorinated hydrocarbons fall into two classes, in both of which there is an approximate positive correlation between toxicity to Musca and to Glossina. One class, including Telodrin, Thiodan and Bromodan, is exceptionally toxic to tsetse and more than 40 times as toxic to Glossina as to Musca. These have a molecule with a particular type of nucleus (hexachloro-l,4-methano-cyclohexene) with a single bridged unsaturated ring. The more common chlorinated hydrocarbons (γ BHC, DDT and aldrin) are two to five times, and dieldrin 12 times, as toxic to G. morsitans as to M. domestica, and all are very toxic to both species.

Among organophosphorus compounds there is very little correlation between toxicity to M. domestica and that to G. morsitans, but it appears probable that no compound of low toxicity to Musca (i.e., LD50 of the order of 0·5 µg.) would be likely to compete with those compounds already known to be most toxic to Glossina. Replacement of the nitro group on the benzene ring of Sumithion by a thiomethyl group, to form Baytex, increases toxicity to Glossina fivefold, but that to Musca by only one-fourth. There is less information on organocarbamates, and it may be a coincidence that 2-isopropoxyphenyl N-methylcarbamate, the most toxic of those tested on G. morsitans, was also most toxic to Musca.

The ecology of four tsetse species of the group of Glossina fusca (Wlk.) was studied near the Ugbobigha field station of the West African Institute for Trypanosomiasis Research in southern Nigeria. G. tabaniformis Westw. and G. nigrofusca Newst. occurred in Lowland Rain Forest and G. medicorum Aust. in forest outliers in Derived Savannah; G. fusca was present in both habitats. Meteorological records showed that the climate in the rain-forest was cooler and more humid than in the forest outliers where, in turn, it was more equable than in the savannah. The distribution of the four species, each with its own range of tolerance, was thought to be largely determined by the climatic conditions within the various habitats.

A fly-round, using a white Zebu ox as bait, had been established in the rain-forest in August 1956; 2,549 fusca-group flies were caught in just over three years, 83 per cent, were G. tabaniformis, 16 per cent. G. fusca and 1 per cent. G. nigrofusca. The number of flies caught on the fly-round declined during the catching period; it is suggested that this was caused by the necessity to kill all flies caught in order to identify them. This disadvantage was overcome in further experiments, in which fusca-group flies were caught from an ox tethered in the rain-forest, and in which all flies caught were marked and released; the proportion of each species in the total catch was known, although the identities of individual flies were unknown. A total of 14,577 fusca-group flies were caught once per day during 22 days in July 1957 (wet season) and 7,694 during 22 days in January 1958 (dry season). G. fusca and G. medicorum, which can be readily distinguished on external characteristics, were caught on an ox fly-round laid out in an area of riverine forest in the savannah and further studies on all species were made in a primitive fly-breeding room at Ugbobigha.

G. tabaniformis was most plentiful in the middle of the rains and scarcest during the dry season. Estimation of the numbers of G. tabaniformis and G. fusca combined, during July 1957 and January 1958, suggested that flies were approximately three times more abundant in the rains. The dry-season decrease was considered to have been caused by the adverse effects of high temperatures and low humidities. Largest numbers of G. tabaniformis were caught in those areas of the rain-forest where the host animals, especially the red river hog (Potamochoerus porcus), were least disturbed by human activity. In both wet and dry seasons there were early-morning and late-afternoon and early-evening peaks in activity of G. tabaniformis. It is incorrect to describe the species as crepuscular in habit; during July 1957 flies of a mixed population composed of approximately three-quarters of G. tabaniformis and one-quarter of G. fusca were caught at a rate of only just less than one a minute even when least active. Activity at night was negligible. Analysis of the sex ratio throughout the day showed that rather more than half of the catch of G. tabaniformis before 0700 hr. and after 1800 hr. were males. During the middle of the day females greatly outnumbered males. On the ox fly-round, 58 per cent, of the catch of G. tabaniformis were females; from the tethered ox, 65 per cent, (wet season) and 70 per cent, (dry season) of the mixed catch of G. tabaniformis and G. fusca were females. The percentage of females amongst flies that emerged from puparia of G. tabaniformis in the fly-breeding room was 57.

The numbers of G. fusca caught on the ox fly-round in the rain-forest were insufficient to provide definite evidence for seasonal fluctuations in population density, although such fluctuations probably did occur. In experiments in riverine forest, 2,547 individuals of G. fusca were caught once per day in July–August 1958 (wet season) and 304 in January–February 1959 (dry season). It is suggested that forest outliers in the savannah at Ugbobigha were a suitable habitat during the wet season but that the high temperatures and saturation deficits in the dry season approached the limit of endurance of the species and prevented larger numbers occupying the habitat; mean length of life was probably much reduced in the dry season. G. fusca in the wet season was nearly equally active throughout the day, with a suggestion of peak activity just before dark. In the severe conditions in the dry season in the riverine forest, activity was negligible between about 1200 and 1700 hr. Analysis of the sex ratio of G. fusca in the wet season showed that the proportion of males increased during the day. In the rain-forest, 44 per cent, of the examples of G. fusca caught on the fly-round were females; in the riverine forest 47 per cent, (wet season) and 40 per cent, (dry season) were females. The sexes emerged from the puparia in equal proportions.

Only 29 individuals of G. nigrofusca were caught on the ox fly-round in the rain-forest, of which only three were females.

Only 120 individuals of G. medicorum were caught in the wet-season experiment in the riverine forest and 36 in the dry season; 54 per cent, were females in the wet season and 42 per cent, in the dry season. The flies were most active early in the morning. The emergence rate (82%) from puparia of G. medicorum in the fly-breeding room was higher than for G. tabaniformis (56·5%) and G. fusca (54%).

The types of habitats occupied by the Nigerian species of the fusca group are described.

It is only in recent years that the presence and extent of sleeping sickness amongst the pagan tribes on the Bauchi Plateau have been recognised. This is partly owing to the fact that endemic sleeping sickness of a very mild type with a low mortality has prevailed hitherto. The epidemic disease with a high mortality seems to be of recent origin and is probably due to the improved communications and unrestrained movement between different tribes and races throughout the Province, resulting in the introduction of new and virulent strains of Trypanosoma gambiense. The large labour camps at the tin mines are doubtless responsible for a good deal of this movement of population. Tsetse on the Plateau is usually scanty, as suitably heavy shade and an adequate food supply are comparatively rare. Wherever conditions permit, however, Glossina palpalis is present. The following report is based on a visit made by the author during November and December, 1929, to Ganawuri, where the most severe epidemic of sleeping sickness yet recorded on the Plateau was in progress. The objects of the visit were primarily an investigation into the bionomics of G. palpalis in this locality, and the determination of the part played by it in the transmission of the disease.

Twenty one species of ticks (Ixodoidea), one of which is represented by two subspecies, are recorded from the Bechuanaland Protectorate. Localities, dates and the hosts are given; general distribution and medical and veterinary importance are discussed under each species.

The shrub desert formations of the Kalahari are shown to be unsuitable habitats for most species of ticks; only a few are able to survive under severe desert conditions.

In medical respects, Ornithodoros moubata (Murr.), as the transmitter of relapsing fever, is the most important tick in the Protectorate. It has been found in the eastern part up to Francistown and in Ngamiland and near Tsane; its further distribution has not yet been established. Larvae and nymphs of various members of the Ixodidae infesting domestic and wild rodents are potential transmitters of tick-bite fever.

Cattle in the eastern area and in Ngamiland were found to be infested by ten species, of which Amblyomma hebraeum Koch, Hyalomma rufipes Koch, H. truncatum Koch, Rhipicephalus appendiculatus Neumann, R. evertsi evertsi Neumann, R. simus simus Koch and Boophilus decoloratus (Koch) are the most important ones, both in respect of the numbers infesting cattle, and of their significance as transmitters of redwater, anaplasmosis, heartwater and sweating sickness.

Sheep, goats, pigs and horses were found to be infested by nine of the species listed above as occurring on cattle.

Dogs were mainly parasitised by Rhipicephalus simus which outnumbered by far the two recognised dog-ticks, Rhipicephalus sanguineus sanguineus (Latr.) and Haemaphysalis leachii leachii (Aud.).

Wild Bovids and zebra are infested by species which also live on domestic ruminants, but the percentage of the different species present varies according to the host and to the locality.

Wild carnivores are infested by the same species as are dogs, but in this group, too, there are differences in the relative abundance of the various tick species.

Small birds are hosts of immature stages of Amblyomma and Hyalomma species. Their importance as carriers for the dispersal of cattle-infesting ticks is noticed.

The chalcidoid parasites associated with galls on mango leaves and branches caused by Cecidomyiidae (mainly Procontarinia spp. in India) are taxonomically treated and keyed out. They include ten species belonging to five families (plus one treated elsewhere). The following taxa are described as new: in Torymidae, Mangostigmus gen. n. for Neomegastigmus amraeus Kurian; in Ormyridae, Ormyrulus gibbus gen. et sp. n.; in Pteromalidae, Gastrancistrus (Mangistrus subgen. n.) cherryi sp. n.; and in Eulophidae, Aprostocetus sankarani sp. n., Mangocharis longiscapus gen. et sp. n. and Chrysonotomyia obesula sp. n. The name Gastrancistrus mangiferae Subba Rao is placed in synonymy under G. muneswari Yadav. Two probable new synonymies are suggested under Chrysonotomyia.

1. The egg, vermiform larva, and the nymphal stages of ph. gregaria are described. It is shown that six stages occur, or seven instars including the vermiform larva. These stages can be distinguished by (a) the number of antennal joints, (b) the degree of backward prolongation of the pronotum, (c) the differentiation of the terminal abdominal structures. Measurements of the pronotum and femur served to distinguish the stages in material from the same swarm, but the absolute measurements cannot be used to distinguish material from different sources.

2. The colour pattern of ph. dissocians is analysed, and colour changes are indicated as divergences from the gregaria pattern. Forms of ph. dissocians observed in the field are grouped into several types the relationships of which are illustrated, and the environmental factors which produce them are discussed.

3. Hoppers believed to be of ph. congregans could not be distinguished from certain forms of ph. dissocians.

4. Cage experiments in which hoppers were reared under varying degrees of crowding are described. It is strongly indicated that activity which is induced by crowding influences the development of gregaria colouring. The green colouring of dissocians hoppers appears to be associated with high humidity conditions and the presence of green food. Other colours of dissocians hoppers are conditioned by those of the environment.

5. An aberrant pallid type of hopper is described and its origin is ascribed to the effects of parasitism by Nematodes and possibly also by Dipterous larvae.

6. Certain inferences regarding the processes in the formation of the colour pattern are inferred from a consideration of the effects of parasitism and of dissocians producing factors.

7. The colourings of young adults of ph. gregaria a few days after the ultimate moult and of types taken from large swarms in August are described. It is shown that colour changes occur gradually in the field, the conspicuous pattern of light and dark coloration of the young adult being obscured and finally hidden by the development of a bright red pigmentation.

8. The colouring of young adults of ph. dissocians is described. These show a pattern of light and dark coloration similar to that of the young adult of ph. gregaria, from which it is indistinguishable, immediately after the ultimate moult. In ph. transiens no marked colour change takes place throughout the life of the individual except the development of a purple coloration on the hind wings.

9. Factors influencing adult colouring are discussed. Adults crowded in cages and derived from hoppers reared under crowded conditions did not undergo the colour changes observed in the field. Material taken from large swarms in the field and showing some development of swarm colouring were maintained under crowded and uncrowded conditions. The red pigment of the body changed to a dark brown in both cases. Under uncrowded conditions no further change took place except a conspicuous development of purple coloration on the hind wings in all individuals. Under crowded conditions the brown pigment spread, its final distribution resembling that of the red pigment in later swarm types from the field, but the red colouring of the hind wings was developed only to a very slight extent in a few individuals. In the case of individuals isolated completely the swarm colouring was lost entirely.

10. It is inferred that swarm colouring in the adult is associated with crowding and possibly with activity and that development of the red and purple coloration on the hind wings in gregaria and transiens is affected by different factors and possibly differs in composition.

11. Biometrical data obtained from a variety of types is tabulated and discussed. Material varied from types taken from very large and dense swarms to what might be described as “solitaria beginning to congregate.”

12. It is shown that certain measurable characters, especially the relative size of the sexes, the degree of development of the femur in relation to the wing, and the relative length and degree of constriction of the pronotum differ greatly in gregaria and transiens types and may be used to distinguish them.

13. In the case of material from very large and dense swarms and from very small loose swarms no differences in the characters on which the types could readily be distinguished were observed. It may be that these small groups were derived from larger swarms.

14. Interesting aberrations occur in the case of a swarm believed to have been one of the earliest to migrate any considerable distance after the commencement of swarming. The quantity of material was insufficient to permit of very reliable comparison but it would appear that in these forms the pronotum of the female was generally not shortened or constricted to the same extent as in extreme gregaria, although the construction of the pronotum of the male approximated fairly closely to that of more extreme gregaria

The sampling efficiency of light trap catches relative to human bait catches in estimating biting rates of the mosquito Anopheles gambiae Giles was investigated in two types of community in southern Sierra Leone: (i) where most of the inhabitants slept under treated bed nets; and (ii) where most of the inhabitants slept without bed nets. The number of female A. gambiae mosquitoes caught in these communities by light trap was strongly correlated (r ≥ 0.72) with those from corresponding human biting catches performed either on the same or adjacent nights. It was found that the relative sampling efficiency of light traps varied slightly but significantly with mosquito abundance in villages with treated bed nets, but not in those without them. Nevertheless, the relationship between relative sampling efficiency and mosquito abundance did not differ significantly between the two types of village. Overall, there was insufficient evidence to show that the presence of treated nets altered the relative efficiency of light traps and any bias was only slight, and unlikely to be of any practical importance. Hence, it was concluded that light traps can be used as a surrogate for human bait catches in estimating biting rates of A. gambiae mosquitoes in the two communities.

Pyrethroid insecticides were intensively used against Cydia pomonella in the Río Negro and Neuquén valley, main production area of pome fruits in Argentina. Therefore, the first objective was to evaluate lambda-cyhalothrin resistance levels in C. pomonella larvae from orchards in this area that are currently under pyrethroids treatments. The second objective was to evaluate the frequency of kdr mutation in C. pomonella across Argentina. High levels of resistance to lambda-cyhalothrin (resistance ratios > 30) were determined in all the populations evaluated. The L1014F (kdr) mutation was evaluated in 355 diapausing larvae collected in 12 orchards from San Juan to Santa Cruz provinces (1690 km away from each other). The highest frequency of kdr mutation was determined in larvae from the Río Negro and Neuquén valley (0.61), followed by those from Mendoza (0.36). The kdr allele was absent or present at very low frequencies in orchards subjected to low pyrethroid pressure. The frequency of detection of kdr mutation in C. pomonella from Argentina is related to the use of pyrethroids against this pest in different areas. Target-site insensitivity is, at least, one of the mechanisms involved in resistance to lambda-cyhalothrin in codling moth from the Río Negro and Neuquén valley.

Several species of the genus Cryptolestes Ganglbauer, 1899 (Coleoptera: Laemophloeidae) are commonly found in stored products. In this study, five species of Cryptolestes, with almost worldwide distribution, were obtained from laboratories in China, Czech Republic and the USA: Cryptolestes ferrugineus (Stephens, 1831), Cryptolestes pusillus (Schönherr, 1817), Cryptolestes turcicus (Grouvelle, 1876), Cryptolestes pusilloides (Steel & Howe, 1952) and Cryptolestes capensis (Waltl, 1834). Molecular identification based on a 658 bp fragment from the mitochondrial DNA cytochrome c oxidase subunit I (COI) was adopted to overcome some problems of morphological identification of Cryptolestes species. The utility of COI sequences as DNA barcodes in discriminating the five Cryptolestes species was evaluated on adults and larvae by analysing Kimura 2-parameter distances, phylogenetic tree and haplotype networks. The results showed that molecular approaches based on DNA barcodes were able to accurately identify these species. This is the first study using DNA barcoding to identify Cryptolestes species and the gathered DNA sequences will complement the biological barcode database.

The results of the present investigation can be summarized as follows:—

1. Cold-hardiness in insects depends on the physiological state of the organism; the most resistant are the phases in diapause (prepupae of Croesus septentrionalis, eggs of Lymantria dispar, pupae of Acronyctinae); not so hardy are the caterpillars of Lasiocampa quercus stopped in their development and prepupae of Agrotis segetum; practically non cold-hardy are developing (or growing) insects, viz., the full-grown larvae of Calliphora erythrocephala, the growing caterpillars of Loxostege sticticalis and Agrotis segetum.

2. The difference in the cold-hardiness of these three groups depends on the specificity of their cellular respiration. Growing insects show in their cellular respiration the prevalence of oxydases, the activity of which is connected with characteristics of their cellular structures; in cold-hardy insects the cellular respiration is closely connected with the anoxybiotic processes caused by the dehydrases; their activity is not bound up with the structural elements of the cells, but is closely connected with the presence of non-saturated fat-acids (Dixon, 1929; Meldrum, 1934) peculiar to insect fats.

3. The respiration of growing or developing insects is entirely and rapidly destroyed by narcotics, cyanide and low temperatures; the effect of these agents is due to the destruction of the cellular structures. The respiration of cold-hardy insects is characterised by its definite thermostable part and is also resistant to narcotics (or cyanide, Bodine, 1934). Destroying the cellular structures does not affect that respiration. Cold-hardiness increases with the increase of the percentage of thermostable respiration.

4. Freezing of the protoplasmic water causes the death of an insect only in the absence of thermostable respiration. Many insects in diapause (characterised by a high percentage of thermostable respiration) can be frozen without any lethal effect (Pyrausta nubilalis, Croesus septentrionalis, Lasiocampa quercus). It is clear that the freezing of the free protoplasmic water cannot be considered as an obligatory cause of “ anabiosis.”

5. The quantity of fat does not show any direct connection with thermostable respiration and cold-hardiness in insects. It is probable that the important factor is the quality of the fats, namely, the rôle of non-saturated fat-acids. The increase of cold-hardiness in insects after dehydration can be connected with the changes in cellular respiration; the same can be said regarding the general connection of the water content of the protoplasm and cold-hardiness.

Understanding the mechanisms underpinning spatiotemporal diversity patterns of biological communities is a major goal of ecology. We aimed to test two ecological hypotheses: (i) temporal patterns of β-diversity will mostly be driven by nestedness, with a loss of species from summer to winter, and (ii) nestedness values will correlate with climatic variables instead of turnover values, indicating either a loss of species during winter or a gain of species during summer. We sampled dung beetles using standardized sampling protocols along a year in four Atlantic forest sites: two at the northwest and two at the central region of Rio Grande do Sul state, southern Brazil. We partitioned temporal patterns of β-diversity into turnover and nestedness in order to investigate if community changes are driven by species substitution or gain/loss across time. Our results highlighted five main findings: (i) dung beetle composition varied more with sites than site geographic position; (ii) there was almost one and a half ‘true’ dung beetle assemblages regarding the spatial distribution of species weighed by abundance; (iii) we found a positive influence of mean temperature and a negative influence of relative humidity on both species richness and abundance; (iv) both spatial and temporal dissimilarity among sites were dominated by species replacement, while the relative importance of nestedness was higher in temporal than spatial patterns; (v) there was an effect of precipitation and relative humidity on temporal patterns of β-diversity components, but these effects were site-dependent. Contrary to our expectations, the β-diversity component of turnover dominated both spatial and temporal patterns in dung beetle dissimilarity among sites and months. Distinct climatic variables affected differently the α-diversity and β-diversity components of dung beetle assemblages. Partitioning β-diversity into temporal components is a promising approach to unveil patterns of the community dynamics and to produce insights on mechanisms underlying such patterns.

Field studies in Zimbabwe elucidated how trees might be enhanced as baits for controlling Glossina morsitans morsitans Westwood and G. pallidipes Austen. Catches from electrocuting devices at the bases of trees were near nil when sampling tsetse flies landing on the trunk but much greater when sampling them flying within 1 m of the trunk. Catches increased 5–8 times when 2 m2 of the trunk were blackened and given odour of acetone, 1-octen-3-ol, 3-n-propyl phenol and 4-methyl phenol, but were still only ca. 30% of the catches from an odour-baited, free-standing, 1 × 1 m screen of black cloth. The upright trunk of real and model trees hindered their attractiveness but leaves and branches 5 m above ground had no clear effect. Real and artificial stumps of trees were as effective as the screen if they were 1 m2, compact and sharply outlined. The practical and biological implications of the results are discussed, with particular reference to the use of insecticide-treated netting with modified tree stumps as baits for control.

The effects of pockets of damp wheat upon the spatial structure (dispersion) of experimental populations of adults of Cryptolestes ferrugineus (Steph.) were investigated in the laboratory. Isolated pockets of non-mouldy wheat of 18 per cent, moisture content (85 per cent. R.H.) and of equally moist wheat supporting a mould flora (mainly Aspergillus candidus) were placed in a larger bulk of wheat of 14 per cent, moisture content (70 per cent. R.H.) at 25°C. One hundred beetles were released at the centre of the top surface of the bulk, and their dispersion within it was observed one week later. The method used allowed the entire bulk (25 kg.) to be quickly broken down so that the relative numbers of individuals in each of the 64 cubes of which it was composed could be recorded. Using other apparatus, the responses of single, isolated individuals to these physical conditions were analysed.

Insects reared at 25°C. and 70 per cent. R.H. accumulated to an equal extent in the pockets of damp wheat irrespective of whether it was mouldy or not. Insects in a preferendum arena went to the drier side, i.e., to 70 per cent, as opposed to 85 per cent. R.H., and the underlying mechanism was found to be a klinokinetic response to humidity. Maintaining insects at 40 or 85 per cent. R.H. for 14 days before testing did not alter their dispersion behaviour in bulks of grain; maintenance at 40 per cent. R.H. did not alter their response to humidity in a preferendum arena, but at 80 per cent. R.H. it was abolished.

A study of oviposition behaviour showed that when there was a choice between wheat of 18 and 14 per cent, moisture content, nearly all the eggs were laid in the damper grain, both when it was mouldy and when it was not. It is considered that oviposition requirements, and to some extent trophic behaviour patterns, over-ride the hygrokinetic response when wheat is damp or damaged, but that under field conditions, where the presence of dust and broken grain throughout the bulk provide conditions suited for oviposition and feeding, accumulations due solely to hygrokinesis may occur in the drier parts of a bulk.

The results are discussed in relation to the ecology of the species in grain and to its detection and control; and evidence from this and other studies is discussed in relation to the dynamic nature of spatial organisation of insect populations in grain.

The loss of crop following insect attack on cotton was studied in 1950–54 at the Cotton Research Station, Namulonge, which is situated in the elephant-grass zone of Uganda, in which the principal pest of cotton was originally considered to be Lygus vosseleri Popp. In 1953, the main invasion of cotton by Lygus occurred during September and October, originating from cultivated crops of black gram (Phaseolus mungo) and sorghum and from the wild perennial legume, Pseudarthria sp., which earlier workers had considered important. Trials in this zone have demonstrated, over a number of years, that early June is the optimum date for sowing cotton, although such sowings receive the heaviest attack by L. vosseleri. Experiments to determine the maximum loss of yield due to Lygus should therefore be made with cotton sown at this time. Bollworms are also important pests, notably Heliothis armigera (Hb.) and Earias spp., their attacks following those of Lygus and being heaviest in October–November.

Domesticating anopheline species from wild isolates provides an important laboratory tool but requires detailed knowledge of their natural biology and ecology, especially the natural breeding habitats of immature stages. The aim of this study was to determine the optimal values of some parameters of Anopheles gambiae larval development, so as to design a standard rearing protocol of highland isolates, which would ensure: the biggest fourth instars, the highest pupae productivity, the shortest duration of the larval stage and the best synchronization of pupation. The density of larvae, the size of breeding water and the quantity of food supplied were tested for their effect on larval growth. Moreover, three cheap foodstuffs were selected and tested for their capability to improve the breeding yield versus TetraMin® as the standard control. The larval density was a very sensitive parameter. Its optimal value, which was found to be ≈1 cm−2 surface area, yielded a daily pupation peak of 38.7% on day 8 post-oviposition, and a global pupae productivity of 78.7% over a duration range of three days. Anopheles gambiae's larval growth, survival and developmental synchronization were density-dependent, and this species responded to overcrowding by producing smaller fourth instars and fewer pupae, over elongated immature lifetime and duration range of pupae occurrence, as a consequence of intraspecific competition. While shallow breeding waters (<3 cm) produced a higher number of pupae than deeper ones, no effect of the breeding habitat's absolute surface area on larval development was observed. Increasing the daily food supply improved the pupae productivity but also boosted the water pollution level (which was assessed by the biological oxygen demand (BOD) and the chemical oxygen demand (COD)) up to a limit depending on the food quality, above which a rapid increase in larval mortality was recorded. The food quality that could substitute the manufactured baby fish food was obtained with weighed mixture of 1 wheat+1 shrimp+2 fish. On establishing an anopheline mosquito colony in the laboratory, special care should be taken to design and maintain the appropriate optimal values of larval density, water depth, daily diet quantity and nutritional quality.

This paper describes the derivation of a compound shape measure for discriminating between populations of the desert locust, Schistocerca gregaria (Forsk.). The discriminant is the first canonical variate and is based on measurements of three parameters for samples from twelve locust populations. It is argued that the first canonical variate is a measure of phase.

Severe defoliation of cassava by Zonocerus variegatus (L.) can occur every year during the dry season in southern Nigeria, but the effect of such defoliation on tuber yield was not known. Experiments simulating different forms of damage and direct observation on damage by Z. variegatus indicated that tuber yield is reduced significantly by defoliation only towards the end of the dry season after natural leaf regeneration has begun, when its effect is to delay regeneration so that damaged plants lag behind those which are undamaged. Continuous defoliation over six weeks at the end of the dry season caused a mean crop loss of 63%, and simulated debarking a mean loss of 49%. Z. variegatus confined in plots until the end of the dry season caused a mean loss of 36%, losses being less than those caused by simulated defoliation because cropping took place sooner after the end of defoliation. Defoliation during the dry season caused no significant crop loss when damage occurred before leaf regeneration at the beginning of the following wet season. Monitoring of natural defoliation by Zonocerus in successive years showed there were considerable differences in amount and timing. It is concluded that crop loss due to Zonocerus damage is significant only occasionally despite defoliation occuring every year.

The observations here recorded were made during the rearing of Alysia manducator, Panz., as a parasite for Australasian sheep-maggots by the Imperial Bureau of Entomology, and are published by permission of the Director, Dr. G. A. K. Marshall. They form merely a supplement to the accounts of this species included in two excellent papers by G. S. Graham-Smith (1916, 1919), and one equally thorough by G. M. Altson (1920).

The present studies were carried out in North Essex during August-November, 1926. I am very much indebted to Mr. B. Golding and Miss Golding, for giving me all possible facilities for working at Street Farm, Ashen ; and to my wife for keeping the time during the heart-beat observations.

Alysia manducator is a blackish, rather stoutly-built Braconid about a quarter of an inch in length. The female lays usually one egg in a Muscid maggot of considerable size. Very little further development appears to take place until the maggot pupates, when the Alysia larva rapidly consumes it and accomplishes its own metamorphosis within a silken cocoon with which it lines the puparium. The adult Braconid emerges a few weeks later at the anterior end of the puparium ; but eggs deposited in autumn do not complete their cycle until the following year, when about a third of the imagines appear in spring and two-thirds in the following autumn (Graham-Smith). No hyperparasites are known, but Graham-Smith has recorded destructive superparasitism by Melittobia acasta, Walk. (1916, pp. 533–535), and by Mormoniella (Nasonia) brevicornis, Ashm. (1919, p. 378). Altson (1920) has shown that buried puparia are normally beyond the reach of Mormoniella, which is not adapted for burrowing.