The significance of Glossina morsitans submorsitans Newst. to the livestock economy of Northern Nigeria is mentioned. Differences in the ecology of the fly have been noted in the Guinea and Sudan savannah zones, respectively. In the former, its distribution is relatively widespread and diffuse, whereas in the latter it is restricted to linear strips associated with river flood plains. The area dealt with in the present work lies in the Sudan zone. The relationship of the fly to its vegetational environment is described, there being a marked concentration of almost the whole tsetse population in evergreen forest islands of relatively limited extent in the second half of the dry season. The source of food is mainly warthog, which were numerous in the area.

A focus of the fly, covering an area of seven square miles, in which the dryseason concentration sites, mainly forest islands, amounted to approximately 200 acres, was selected for an experiment. It was isolated from the main focus by a natural barrier five miles wide.

Possible eradication measures in this focus are mentioned and reasons given for adopting the application of a residual insecticide.

DDT, in the form of a 50 per cent, wettable powder as a 5 per cent, suspension of actual DDT in water, was applied, during the second half of the dry season, at an estimated rate of 20 lb. per acre to the evergreen forest islands, which had previously had paths slashed around and through them. Pneumatic knapsack sprayers were used. A preliminary trial showed that, for up to six weeks after application of the insecticide, examples of G. morsitans from unsprayed forest, placed in contact with sprayed leaves and bark, died in three hours, controls remaining alive for 24 hours. It is suggested that this good persistence may be attributable to the fact that the treated surfaces were in the shade, and that the application was made during the rainless season and at a time when the vegetation was dormant. There was a rapid decline in the population of G. morsitans after spraying. The flies persisted longest (5 weeks) in a site associated with Mitragyna inermis. One application only was given to one part of the focus and in many others one application would probably have sufficed, the second being given in most instances to control G. tachinoides Westw., which was also present, and only in two instances for the eradication of G. morsitans that persisted after the first application. One of these was the site associated with Mitragyna inermis, mentioned above. The last specimen of G. morsitans was caught five weeks after the first application, and none has been caught in the sprayed area for up to 18 months after spraying. The cost of the insecticide and labour to apply it amounted to £700 for an area of seven square miles of focus in which the dryseason concentration sites to which insecticide was applied amounted to approximately 200 acres. The final result regarding G. tachinoides was indefinite for reasons which are mentioned.

The larvae of certain gall midges have been known for a long time to prey on Aphids ; in fact Rondani in 1847 described a midge, now known as Phaenobremia aphidimyza, Rond., whose larvae fed on Aphids on fruit trees. Since this first record, there have been many notes of Aphids being attacked by Cecidomyid larvae, and in some cases the adult midge has been reared and described. Most of the literature consists of mere records of larvae feeding on Aphids or else descriptions of the midges ; in a few cases biological notes are added. So far as the writer knows there are only two papers that are devoted to a study of midges as a potential natural control of Aphids. Further work is badly needed to find out whether midge larvae can, or do, act as control agents. There have been vague statements that Aphids in certain outbreaks have been controlled by the midge larvae, but so far there have been no exact proofs based on counts of numbers of Aphids killed, fecundity of midge compared with Aphid, the appetite of the midge larvae, etc.

Annual variation in flood frequency and hydroperiod during the vegetation season has ecological impacts on the floodplain biota. Although many insect groups may have a lower emergence during a flood event, it is poorly known how annual emergence of insects in temporary wetlands is related to the variation in hydrology. Between May and September, we studied the weekly emergence of 18 insect taxa over six consecutive years, 2002–2007, in six temporary flooded wetlands (four wet meadows and two forest swamps) in the River Dalälven floodplains, Central Sweden. We used emergence traps to collect emerging insects from terrestrial and aquatic parts of wet meadows and swamp forests. In all wetlands, the insect fauna was numerically dominated by the orders Diptera, Hymenoptera, Coleoptera and Homoptera. On a weekly basis, 9 out of the 18 insect taxa had lower emergence in weeks with flood than in weeks with no flood, whereas no taxon had a higher emergence in weeks with flood. Over the seasons, we related insect emergence to seasonal flood frequency and length of hydroperiod. The emergence of most studied taxa decreased with increasing hydroperiod, which suggests that emergence after floods do not compensate for the reduced emergence during floods. Only Culicidae and the aquatic Chironomidae sub-families Tanypodinae and Chironominae showed an increase in emergence with increasing hydroperiod, whereas Staphylinidae peaked at intermediate hydroperiod. We conclude that a hydroperiod covering up to 40% of the vegetation season has a significant negative effect on the emergence of most taxa and that only a few taxa occurring in the temporary wetlands are actually favoured by a flood regime with recurrent and unpredictable floods.

Phenol, also known as carbolic acid or phenic acid, is a priority pollutant in aquatic ecosystems. The present study has investigated metabolic activities and transcription profiles of cytochrome P450 enzymes in Chironomus kiinensis under phenol stress. Exposure of C. kiinensis larvae to three sublethal doses of phenol (1, 10 and 100 µM) inhibited cytochrome P450 enzyme activity during the 96 h exposure period. The P450 activity measured after the 24 h exposure to phenol stress could be used to assess the level (low or high) of phenol contamination in the environment. To investigate the potential of cytochrome P450 genes as molecular biomarkers to monitor phenol contamination, the cDNA of ten CYP6 genes from the transcriptome of C. kiinensis were identified and sequenced. The open reading frames of the CYP6 genes ranged from 1266 to 1587 bp, encoding deduced polypeptides composed of between 421 and 528 amino acids, with predicted molecular masses from 49.01 to 61.94 kDa and isoelectric points (PI) from 6.01 to 8.89. Among the CYP6 genes, the mRNA expression levels of the CYP6EW3, CYP6EV9, CYP6FV1 and CYP6FV2 genes significantly altered in response to phenol exposure; therefore, these genes could potentially serve as biomarkers in the environment. This study shows that P450 activity combined with one or multiple CYP6 genes could be used to monitor phenol pollution.

(1) In seepage-filled borrow-pits in South India it was observed that there was a progressive decline in the density of larvae of Anopheles culicifacies, Giles, as the pits became older. The largest numbers of larvae were tound soon after water entered the newly-dug pits.

(2) There was less ovipositing by culicifacies in older pits than in new ones dug late in the irrigation season. Newer pits seemed definitely more attractive in this species than older ones. These newer pits sheltered more culicifacies larvae late in the season than the older pits.

(3) The decline of culicifacies larva density in a borrow-pit seemed to be due mainly to factors internal to the pits. There was no evidence of the influence of external factors, except from October to January, when perhaps meteorological influences supplemented the internal factors. The attractiveness of new borrow-pits to culicifacies appeared to be due mainly to internal factors.

(4) Certain simple factors studied did not seem to have any significance in relation to culicifacies density in the pits. Rainfall, predators, macroscopic vegetation, pH, CO2, dissolved oxygen, bicarbonate alkalinity, ratio of free to bound and half bound CO2, hardness, chlorine, ammoniacal nitrogen, nitrates, nitrites, sulfates and iron, appeared to have no significance in this regard. Albuminoid nitrogen and oxygen absorbed perhaps had some significance, which was not clear.

(5) Among planktonic organisms, the individual groups of organisms, such as green algae, diatoms, rotifers, and copepods, definitely showed no relation to culicifacies breeding. Protozoa as a group appeared to be negatively associated to a slight degree. Blue-green algae also seemed to have a negative association.

(6) Amorphous organic matter and total plankton, however, showed statistically significant negative association with larval density of culicifacies The decline in culicifacies larvae was clearly associated with increase in total plankton and amorphous matter. The attractiveness of new borrow-pits also seemed to be related to their low total plankton content.

(7) The exact manner in which the total organic matter acted as an inhibitory factor against culicifacies breeding was not determined.

Puparia of Glossina austeni Newst. and G. morsitans Westw. contain similar quantities of chloroform-soluble substances (referred to as fat) in relation to their nonfatty dry weight at the beginning of puparial life. However, adult G. austeni emerge from their puparia with significantly larger fat reserves than G. morsitans after development at 25°C. This obvious difference in the rate of fat consumption by puparia of the two species is not accompanied by differences in the rate of oxygen consumption, neither do respiratory quotients explain the difference. It is therefore concluded that some substrate other than fat may be used as a supplementary energy source in G. austeni, since there appears to be no species difference in the composition of fat. Thus the calculation of an oxygen equivalence of fat for tsetse flies is invalid for different species and may also vary within a species depending upon the temperature at which development proceeds.

The administration of dieldrin in the larval diet of Lucilia cuprina (Wied.) killed susceptible females with no pre-emergence mortality of males in a strain which contained a Y–autosome translocation linking dieldrin-resistance to the male sex. Laboratory assays of flight activity, sexual competitiveness and visual sensitivity revealed no significant differences between treated and untreated males. The life-span of treated males was slightly reduced at the highest dieldrin concentration used. In field releases, however, the recapture rate of treated males was much lower than for untreated males, indicating a major deficiency in the performance of dieldrin-treated males in the field that was not suspected from the laboratory tests.

An odour-baited electric net placed in thick bush caught more Glossina pallidipes Austen when sited at ground level (0.2–1.2 m) than when sited in the top of the bush (1.4–2.4 m) or just above it (2.6–3.6 m). However, a similar net running concurrently 4 m away in a game trail through the bush caught far more flies. When electric nets were placed in the centre of two adjacent game trails in this bush and then one of the trails was barricaded with branches from nearby bushes, the catch declined in that trail and increased proportionately in the other. It is inferred that tsetse flies navigate up host odour plumes by finding gaps in thick vegetation rather than by flying over the top or through it, and that game trails are important forms of such gaps. The implications for siting traps and targets are noted.

This is the second of a series of papers dealing with zoophagous gall midges of the world. The first, “Gall Midges as Enemies of Aphids,” appeared recently (Bull. Ent. Res., xx, 1929, pp. 433–442), while the third dealing with gall midges as enemies of mites is in course of preparation.

Considerable difficulties have been experienced in the past in keeping adults of the Red Locust, Nomadacris septemfasciata (Serv.), alive in cages for any length of time. No satisfactory explanation as to why they die in captivity has so far been given (Hamilton, 1936).

The present paper is an account of a preliminary reconnaissance, undertaken during the wet season of 1932, of the suspected middle Niger outbreak area of the migratory locust, Locusta migratoria migratorioides, R. & F.

Radar methods have been extended to measure the aerial density of small insects. Results obtained during an outbreak of the cereal aphid Metopolophium dirhodum (Walker) in south-eastern England were compared with simultaneous suction trap catches to study the sensitivity of trap effectiveness to windspeed. Two traps were studied: the Rothamsted Insect Survey trap (12·2-m) and a standard aerofoil trap. The Survey trap effectiveness is moderately sensitive to windspeed, decreasing exponentially by a factor of two for each 2·4 m/s (5 knots) of average windspeed. The two trap sensitivities did not differ significantly, but both results are very significantly different (P>0·001) from the published predictions, which were based upon a comparison of catches from suction traps and a combination of a rotary (whirligig) net and a tow net. These differences are discussed. The average catching rate is about 40% of that of an ideal trap. Seven-day catches could vary by a factor of 0·5—2·0 from average due to prolonged periods of extra strong or light winds. Systematic windspeed gradients can corrupt suction trap studies of insect dispersal in relation to vertical density profiles, diurnal flight patterns and geographical distribution. Absolute calibration of the aerofoil trap was achieved by using the remote-sensing IRADIT infra-red system to measure the aerial density of aphid-size insects near to the trap inlet in very light winds; the effectiveness was not statistically different from unity, and the Survey trap is expected to perform similarly.

A relationship between mean development rate, temperature and saturation deficit was derived for the egg stage of Lucilia cuprina (Wied.). Development rate increased linearly with temperature between 10 and 40°C at constant saturation deficits. Increasing saturation deficits between 0 and 10 mm Hg caused non-linear decreases in development rate. At zero saturation deficit, temperatures between 15 and 40°C had no effect on egg survival. Survival in the egg stage declined rapidly with increasing saturation deficits, primarily through the inability of the larvae to rupture the chorion of the egg. The aggregation of single eggs into compact egg-masses during oviposition appeared to afford no additional protection against desiccation. The ecological implications of the results are discussed.

The salient points in Pallas's brief description are as follows:—“Cinereus … Frons hirtella. Antennae triarticulatae; extremum trinode, basis vero pilis nigris subpennata. Palmi [? palpi] nulli: ensis nudus … basi pilosus. Pedes longissimi, grisei, posticis corporis fere tripla longitudine, praesertim tarsi, elongati. Alae lanceolatae, cinerascentes, venis hirsutis ad crassiorem marginem nigro maculatae … Comes prioris [C.caspius, = O.dorsalis, Mg.], rarior red ferocior.”

A survey for ticks on livestock with emphasis on ticks parasitizing cattle was conducted below 16°N lat. in Mali. Seventeen species of ixodid ticks were recovered from cattle, 12 from sheep, five from goat, four from horse, one from donkey and four from camel. Amblyomma variegatum (F.), Boophilus geigyi Aeschlimann & Morel, Hyalomma marginatum rufipes Koch and H. truncatum Koch were widespread, and could each be collected as adults from cattle throughout the year in certain regions. A. variegatum was most numerous from the tropical woodlands to the Sahelo-Sudanian steppe. The prevalence of B. geigyi in Mali confirms an extended distribution of this species in West Africa. B. annulatus (Say) and B. decoloratus (Koch) were prevalent in the inland delta area and in south-western Mali. H. m. rufipes and H. truncatum were most numerous in the Sudanian and Sahelo-Sudanian steppe. H. dromedarii Koch, H. impeltatum Schulze & Schlottke and H. impressum Koch were collected in the steppeland areas. H. nitidum Schulze was collected for the first time in Mali. This comparatively more hydrophilic species was prevalent in the North Guinean forest and Sudano-Guinean vegetation zones. Of eight Rhipicephalus species from livestock, seven were collected from cattle: R. cuspidatus Neumann, R. evertsi evertsi Neumann, R. guilhoni Morel & Vassiliades, R. muhsamae Morel & Vassiliades, R. sanguineus (Latreille), R. senegalensis Koch and R. lunulatus Neumann. R. sulcatus Neumann was obtained only from sheep. The distribution and phytoclimatic associations of these species are discussed.

Series of 24-hour catches at different levels were made at Zika and Lunyo in the Entebbe area, Uganda, using fowls (White Leghorn cocks) as bait, and some comparative catches were made with man as bait.

Thirty-seven different mosquito species (including five species groups) were taken on the avian bait.

The vertical distributions and biting cycles of each of nine species (including one species group), Anopheles implexus (Theo.), Mansonia (Coquillettidia) aurites (Theo.) gp., M. (C.) fuscopennata (Theo.), M. (Mansonioides) africana (Theo.), Hodgesia cyptopus Theo., Aedes africanus (Theo.), A. apicoargenteus (Theo.), A. ingrami Edw. and Culex annulioris Theo. were similar on human and avian bait.

At Lunyo both A. africanus and C. annulioris had a marked diurnal peak, which had not been described previously.

Comparison of the numbers coming to avian and human bait indicate that species of Culex, H. cyptopus and most of the species of Mansonia (Coquillettidia) have a preference for birds.

Immature nutfall, caused by the Coreid, Amblypelta cocophaga China, was prevalent in the coconut plantations of the British Solomon Islands before the late war, and was increasing in extent and intensity. Good crops were borne by palms inhabited by colonies of Oecophylla smaragdina (F.), as this ant destroyed Amblypelta; and the same was true, to a lesser extent, of another ant, Anoplolepis longipes (Jerd.). The smaller species, Pheidole megacephala (F.) and Iridomyrmex myrmecodiae Emery, did not destroy Amblypelta and consequently palms bearing these species suffered from nutfall. These non-beneficial ants were extending their areas of occupation and becoming dominant in the plantations of the Protectorate.

Attempts to control Amblypelta by introducing parasites from Indonesia, Queensland and Fiji have all proved ineffective, and so also have past efforts to change the balance of ant populations in the plantations in favour of the beneficial species.

After the war, it was noticed that certain plantations in Guadalcanal, which had suffered severely from nutfall for several years, were recovering and bearing well. In 1948, it was found that this recovery was correlated with changes in the ant populations, Oecophylla having occupied much of the area, displacing Pheidole, which had previously been dominant. The investigators concluded that this was due to ecological changes in the. plantation undergrowth, resulting from neglect of cleaning and brushing during the war.

The present paper deals with a re-examination of the position in 1952–53. The author found a further improvement in the yield and an extension of the area of recovery on the plantation in question; Pheidole had completely disappeared, but in many parts Oecophylla had been driven back by Anoplolepis, which had now become the dominant ant. The only nutfall areas that remained here were occupied by Iridomyrmex.

A fuller examination of these and other plantations did not support the theory that nutfall recovery was due to ecological changes in the undergrowth, for these had occurred everywhere in the Protectorate during the war, yet on most other plantations yields had decreased, and Pheidole had greatly extended its pre-war area of occupation. The areas in which recovery had occurred were adjacent to wartime military installations that had been subject to regular weekly anti-malarial spraying from the air, and it is suggested that this had affected Amblypelta, both directly, and indirectly by having differentially affected the populations of Pheidole and Oecophylla. It seemed more likely that it had been caused by the long-sustained spraying programme carried out by the United States forces during and after the war.

Small-scale tests carried out with insecticidal sprays confirmed this theory: the harmful species, Pheidole and Iridomyrmex, were found to be very severely affected, while the beneficial ones, Oecophylla and Anoplolepis, suffered far less. In plots with mixed ant populations it was found possible to increase temporarily the number of palms occupied by beneficial species by spraying the palm-bases with insecticide. With the equipment available it was not possible to spray the boles and crowns: consequently, these trees were often reoccupied later by the harmful species Iridomyrmex from colonies in the crowns.

The sprays were also found to be fatal to Coreid bugs, both on contact and for a considerable residual period.

The two weevils Ceutorhynchus geographicus (Goeze) and C. larvatus Schultze, which live and develop on Echium plantagineum (Boraginaceae) in the western Mediterranean regions, are potential biological control agents for this plant, which is an important weed in Australia. Adults bite holes in the leaves and petioles, but this damage is not great in comparison with that caused by their larvae, which mine the collar and root, causing massive necrosis and often the death of the plant. C. larvatus larvae are found especially in the aerial parts of the collar of the plant, while those of C. geographicus attack principally the rootstocks. Quarantine safety testing was based on plants selected by the criteria already used for the Echium leaf–miner Dialectica scalariella (Zell.), and it was confirmed that the two weevils would be safe and effective agents for the biological control of E. plantagineum in Australia.

Residues of pirimicarb or deltamethrin plus heptenophos on potatoes in field cages in southern England reduced artificial infestations of susceptible and insecticide-resistant strains of Myzus persicae (Sulzer) introduced up to 14 days after treatment. Deltamethrin plus heptenophos gave better control than pirimicarb, particularly of nymphs, but also selected more strongly for very resistant (R2) aphids. Susceptible (S) aphids survived the treatment with deltamethrin plus heptenophos better than moderately resistant (R1) aphids, probably due to a different or more pronounced behavioural response to the pyrethroid. However, the combination of the greater persistence of deltamethrin plus heptenophos and the high resistance of M. persicae to the pyrethroid led to more prolonged selection for R2 aphids, which is sometimes associated with a resurgence in aphid numbers.

In cockchafers of the genus Melolontha, there is a marked intraspecific polymorphism for morphological characters, making some specimens of one species resemble another. A cytogenetic and molecular (mitochondrial COI gene sequence) study of typical and atypical forms of M. melolontha and M. hippocastani, captured at the same period and area, was performed. Karyotypes and haplotypes clearly characterize each taxon, placing atypical specimens in one or the other species unambiguously. This formally discards the role of hybridization in phenotypic resemblance, as usually proposed. Karyotypes and haplotypes were compared to those of M. pectoralis and Phyllophaga pleei, a more distantly related Melolonthinae, and some Dynastinae species, to reconstruct their ancestral karyotype. The karyotype of M. melolontha is the most derivative and that of P. pleei the most conserved among the Melolonthinae studied, which fits with the phylogeny established by COI gene analysis. Both karyotypes and COI haplotypes demonstrate the proximity of M. pectoralis and M. melolontha. The karyotype of M. melolontha is polymorphic, without relationship with morphological variations. Finally, the existence of similar morphological variations in different Melolontha species and chromosomal polymorphism in M. melolontha is discussed in relation with a network (reticulated) mode of speciation.