Two experiments are described where applications of coarse aerosols have been made to areas of savannah woodland infested with tsetse flies (Glossina spp.).

The applications were made at nominal dosages of 0·25 gallons per acre, which was equivalent to either 0·20 lb. of p.p′DDT per acre, or 0·03 lb. of γ BHC per acre. The coarse aerosols had mass median diameters of approximately 60 microns.

In one experiment, carried out at Urambo, Tanganyika, a reduction of 95 per cent, was obtained in populations of G. morsitans Westw. This kill was somewhat lower than in many other experiments, a fact that can be attributed mainly to our inability to maintain the cycle of applications. Immigration of flies into the treated area caused a relatively rapid increase in fly numbers to levels comparable to the pre-treatment populations, and in this respect the experiment was a failure.

The other experiment, in Lango County, Uganda, was highly successful, and reduced a population of G. morsitans to 0·05 per cent, of its pre-treatment level, and eradicated a small population of G. pallidipes Aust. It is indeed likely that no stable population now exists in the area, and that the very few flies caught there since the end of the applications have been wanderers from other infested woodland. The continued success of the experiment is considered to be due to the effective isolation of the area.

Some brief comments are made upon the costs of the method, and on its value under conditions of land development in Africa.

There is a clear diurnal rhythm in the emergence of the Beet Fly, Pegomyia betae (Curt.), from the soil, peak emergence occurring daily between 06. and 07. hr., when the soil temperature at a depth of 2 in. and the air temperature are at about their minimum, or are just beginning to rise, and humidity is at its maximum. In two observations on the emergence of the first generation, 82·2 and 85·6 per cent, of the daily emergence occurred before 08. hr., whilst in two observations on the emergence of the adults of the non-diapausing part of the second generation, 79·1 and 76·3 per cent, of the daily emergence occurred before 08. hr.

During the period of emergence of flies from a batch of puparia, the rhythm was most marked at the time of peak emergence, and was less marked at the beginning and end of the emergence period.

The rhythm of emergence was much less pronounced, and the peak occurred later in the day, when puparia were kept at constant temperature from two days before the first flies emerged.

Experiments led to the conclusion that the fly reaches the soil surface within one hour of leaving the puparium at a depth of 2 in. in soil, and that the processes of wing expansion and cuticle tanning are probably controlled by a nervous mechanism.

The possible initiators of the diurnal rhythm are discussed. It is concluded that the results obtained could be explained by the suggestion that the rhythm is induced by the effect of temperature or light fluctuation at some time before the late pupal stage, or that it might be inborn in the species, and that it is further regulated by temperature variation at the time of emergence. Further work will be necessary before the suggested explanation can be shown to be valid or otherwise.

A summary is made of the literature dealing with the bionomics of Aphomia gularis (Zell.), a storage pest of almonds, walnuts, groundnuts and prunes, and to a lesser extent of rice and grain. Additional information is also given on its habits and occurrence in Britain.

An outline is given of its origins, introduction and establishment in various parts of the world. The evidence leaves little doubt that the species originated in south-east Asia, its occurrence elsewhere being, with few exceptions, confined to the major ports of western Europe and North America. Cases of the spread of the pest from south-east Asia can be traced to the export of infested goods from that area. Unless action is taken to prevent further dispersal and measures applied to wipe out the known centres of infestation, further establishment of this species can be expected in countries at present not affected.

It would appear that A. gularis is a subtropical and warm-temperate species, rarely found in the tropics and only able to maintain itself towards the northerly limits of its range, as in northern Britain and Sweden, in heated premises. In the cooler temperate regions, such as Britain, it cannot compete with such species as Ephestia elutella (Hb.) while in the tropics its ecological niche is filled by the very closely related species Corcyra cephalonica (Stnt.).

Its apparent absence from regions in the southern hemisphere, where conditions favourable for development exist, may be due to its presence not having yet been recognised.

A portable wooden hut with two windows, on opposite sides, fitted with traps to catch mosquitos as they entered the hut was tried, with human bait, as a sampling device for mixed populations of Anopheles gambiae Giles and A. gambiae var. melas Theo. in and near Keneba village in the West Kiang district of the Gambia.

In eighteen night catches, between 24th August and 22nd September 1954, 5,901 females of this species and its variety were taken in the traps, five high catches (642 to 1,240 females) being made before 3rd September and thirteen low catches (27 to 306 females) between 6th and 22nd September. Possible causes for the different size of catches in the two periods are discussed with the conclusion that the differences in catch are not simply attributable to erratic functioning of the hut as a trap.

Four night catches of 186, 741, 797 and 1,240 females of A. gambiae and its variety are reported in detail. They reveal that mosquitos were taken virtually exclusively in the leeward trap if the wind persisted from one direction. But if the wind was variable, or conditions were calm, they were taken in both traps, entering the traps alternately as the wind shifted in the first instance and, perhaps simultaneously in calm. The results show that the use of only one trap could give misleading information about the numbers of mosquitos available outside the hut.

There is no doubt that, with wind, the mosquitos approached the host in the hut from down-wind. Since much of the catching occurred in darkness it would seem that the mosquitos were attracted by the emanations of the host and that their approach to the hut was not directed by a visual mechanism controlling up-wind flight.

Heavy rain for about seven hours did not prevent flight.

From hourly collections, made from dusk to dawn, a curve of activity for A. gambiae with its variety melas was obtained resembling the biting cycle reported elsewhere by other authors, the greatest activity occurring between midnight and 0600 hr. All the females (except two instances of incomplete fresh blood-meals) were unfed and, in a small sample, ovarian development was stage II or earlier. First entries occurred just before complete darkness in the evening and the last in good light about 30 minutes after sunrise.

No males of A. gambiae or var. melas were taken in the traps.

The numbers, all females, of other species taken were: 1 of A. funestus Giles, 1 of A. rufipes var. ingrami Edw., 59 of Taeniorhynchus (Mansonioides) spp., 30 of Culex nebulosus Theo., 19 of C. thalassius Theo., and 15 of unidentified species. Some Culicoides occurred in the traps and in the hut itself.

The hut, if modified to include a window trap in each of the four walls and a cowl over each window to keep out rain, appears to be a simple and convenient sampling device for certain types of investigations on the biology and behaviour of A. gambiae and its variety melas.

A correction is made to a paper by Nash (1955) in which Syntomosphyrum glossinae Wtstn., a Chalcid parasite of the pupae of tsetse flies, was wrongly recorded as parasitising the oöthecae of Periplaneta americana (L.). The parasite in question was almost certainly the very similar Tetrastichua hagenowii (Ratz.)which is a world-wide parasite of P. americana. There is no evidence that eitherparasite can attack both P. americana and Glossina palpalis (R.-D.).

The biology and general ecology of Melittomma insulare Fairm. in the Seychelles is briefly described and the difficulties in the biological control of this pest are stressed.

As much information as possible was obtained concerning the species of the little-known family Lymexylonidae, particularly with regard to their biology, which in most cases has not been investigated. Several species might warrant further investigation with a view to providing natural enemies for use against M. insulare, but in general what is known of their biology does not afford much hope that an effective parasite or predator will be found.

The biology of Atractocerus brasiliensis Lep. & Serv. was investigated in detail in Trinidad but no natural enemy was found.

The only possibility is that Rhizophagus dispar (Payk.), recorded as attacking Hylecoetus dermestoides (L.) in England, might also attack the eggs of M. insulare.

Forty five species, two subspecies and one variety of Culex occur in the Sudan.

Taxonomic notes are given on a few species, and new localities, mainly for the subgenus Culex, are recorded. The known distribution of all species of this subgenus is shown on maps.

Several aspects of distribution are discussed, and there is a short section on practical importance.

One hundred and fifty six species, two subspecies and seven varieties of Culicidae are known to occur in the Sudan. The present paper shows the known distribution of members of the genera Dixa, Chaoborus, Toxorhynchites, Harpa-gomyia, Hodgesia, Uranotaenia, Aëdomyia, Theobaldia, Ficalbia, Taeniorhynchus and Eretmapodites, and includes taxonomic and other notes on several species.

Some aspects of distribution are discussed, particularly the exchange of species between the Ethiopian and Palaearctic Regions in which movement has been mainly from the latter to the former.

Brief notes are given on the practical importance of some species.

In order to estimate the effect of cracks in floors upon the oviposition rate of Calandra granaria (L.) in an unstocked granary, grain was presented to adults in six ways. The grain was either fixed or loose. Fixation was achieved either by placing grain in cracks in wood or plaster of Paris, or by gumming (in rows or scattered) to glass. The loose grains lay upon glass or plaster of Paris.

A significantly greater number of eggs was laid upon grain that was fixed. The fact that the grains were in rows and partially enclosed when in cracks had no greater effect than fixing with gum. There was no significant departure from a random distribution of eggs in grains when the latter were in cracks.

Independent discoveries of an Aphid attacking the roots of rice and other Gramineae in different parts of the world have led to its description under different names, and its affinity with other species has sometimes resulted in its confusion with them. The literature relating to the species is reviewed and it is shown that the correct name for it is Rhopalosiphum rufiabdominalis (Sasaki), of which Prunus is the primary host.

What is believed to be a reasonably complete synonymy is given and this involves the sinking of the two genera Yamataphis Matsumura and Aresha Mordvilko as synonyms of Rhopalosiphum Koch because both of these genera were erected with the Rice Root Aphid as type. A species that was described as Yamataphis rhodesiensis Hall differs in too many respects to permit its inclusion in Rhopalosiphum and a new genus, Hallaphis, is erected for its reception.

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.

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.

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.

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.

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).