Culicoides anophelis Edw. is of wide occurrence in India, Ceylon, Burma, Malaya, Thailand, Indo-China, Sumatra, Tonkin, and as far as New Britain (Laird, 1946). From India the species has almost invariably been obtained in the act of engorging on female mosquitos, mostly Anophelines (A. annularis Wulp, A. hyrcanus nigerrimus Giles, A. barbirostris Wulp, A. subpictus Grassi, A. vagus Dön., A. aconitus Dön. and A. maculatus Theo.). But the species may also attack members of the Culicini, as observed by Fearnside (1900) in the case of certain unidentified examples of the genus Culex. We have also observed the species attacking Culex pipiens fatigans Wied. and Mansonia (Mansonioides) annulifera (Theo.), which suggests that the occurrance of the species is not so uncommon on members of the Culicini as was thought previously. The reason for the missing of the association of the species with the latter group of mosquitos by most workers seems to lie in the fact that the Culicini were not examined previously in large numbers (Edwards, 1922).

Records of Leucoptera coffeella (Guér.) from Kenya and Tanganyika have been found to be based on misidentifications and to refer to a distinct species, Leucoptera meyricki Ghesq. Other records of coffeella from the Old World seem open to doubt and require to be reinvestigated since they may also be based on misidentifications. L. coffeella seems likely to be a Neotropical species predominant in the West Indies. A lectotype is designated for meyricki, but the type material of coffeella cannot be traced and the identity of the latter species remains to be properly established. The present generic assignment of meyricki and coffeella in the genus Leucoptera Hübn. needs to be reconsidered in the light of the new genus Perileucoptera Silvestri (1943).

The two weevils associated with the living stems of the banana plant in Uganda are Cosmopolites sordidus (Germ.) and Temnoschoita nigroplagiata (Qued.); the damage caused by the former has been known for many years but the latter, which usually breeds in rotting stems, has only recently been shown to attack living ones. T. nigroplagiata occurs in every banana-growing area in the territory and is particularly abundant in some parts of western Uganda where C. sordidus, which is otherwise widespread, is rare or absent. Other species of Temnoschoita associated with the banana plant that occur in Uganda but that are rare, are T. basipennis Duv., bred from larvae in rotting pseudostems, and T. erudita, Duv., known only from the adult.

The full-grown larva of T. nigroplagiata is described in detail and characters are given for separating the larva and pupa of this species from those of C. sordidus.

During 1955 and 1956 two attempts were made to eradicate Glossina, palpalis (R.-D.) and G. tachinoides Westw. from 8¼ miles of heavily forested perennial river in Benue Province of the Northern Kegion of Nigeria by using DDT.

Descriptions of the rivers and the means employed in applying the DDT using knapsack sprayers are given, together with the effect of the insecticide on the fly population.

It was found that it was possible to eliminate G. palpalis from this type of habitat, where the forest is largely restricted to the immediate vicinity of the rivers, but that isolation must be carefully undertaken to prevent reinvasion, which would appear to be more extensive than had been expected. G. palpalis was completely absent for 18 weeks.

G. tachinoides, which was present in much smaller numbers, also disappeared on the treated river, but because of a similar disappearance on the control river it is not possible to attribute this to the insecticidal treatment.

The cost of spraying was about half the cost of clearing by normal current methods.

Six types of habitat in papyrus (Cyperus papyrus) swamps in Uganda were studied with regard to the production of mosquito larvae. A classification, of the types is given, which was largely based on the lapse of time since temporary clearing by cutting or burning had been carried out.

Altogether a total of 5,781 larvae belonging to 17 species was studied. Culex (Culex) guiarti Blanch., C. (C.) univittatus Theo. and C. (Neoculex) rubinotus Theo. were the dominant species, comprising together 78 per cent. of the total number of larvae. Anopheles gambiae Giles was not recorded. Samples of larvae were taken at intervals between mid-January and early April 1957. The sampling method used was unsuitable for those species of which the larvae obtain air from roots or stems of submerged vegetation, and these were excluded from the present study.

There was considerable variation in species and numbers of larvae and in their frequency in the different types of habitat.

It is concluded that (a) peripheral zones, especially in natural untouched swamps, are much more productive than the interior, (b) where swamps have been altered by cutting and by burning of papyrus and other vegetation, burnt habitats, whether recently or after the lapse of up to four or five months, have a very low productivity, (c) of the six chemical factors investigated (pH, K, Na, absorbed oxygen, free and saline ammonia and albuminoid ammonia) only the quantity of soluble organic matter, indicated by absorbed oxygen, and albuminoid ammonia, showed any relation to productivity, the least productive habitats containing the smallest quantity of organic matter.

Other possible factors in swamp water, which were not investigated, are mentioned. These are (a) the nature of soluble oxidisable organic matter, (b) conductivity, (c) ferruginous surface films and (d) iron in solution.

Published records and recent unpublished field observations on Trox procerus Har. in Asia and Africa are assembled. All stages of the life-cycle are figured, and brief descriptive notes on the egg, larval and pupal stages, are given. It is pointed out that the egg and larval stages have only been recorded from egg-fields of the Desert Locust, Schistocerca gregaria (Forsk.), and that the larvae feed on the eggs of the locust, sometimes causing considerable mortality. In contrast, the adults appear to survive independently of the locust, and it is suggested that the apparent concentration of adults of T. procerus in areas where Desert Locusts are ovipositing is due to their being attracted to the numerous dead locusts that are present in such areas.

In continuation of a study of the process of swarm formation in the Red Locust, Nomadacris septemfasciata (Serv.), to enable rational plans for control measures to be made, the population distribution of about 44½ million hoppers of the Red Locust was investigated in an observation area of 1,052 acres in the Iku outbreak area of the Rukwa Valley, Tanganyika Territory, from 18th January to 24th February 1957. to see if the hoppers showed a tendency to concentrate, which would have the effect of producing, immediately after the last moult, adult swarms from hoppers that were originally more scattered. From 25th January onwards, the estimated population remained constant in numbers. Densities over 50 per sq. yd. were unusual and, taking any continuous infestation over one per sq. yd. as a band, the mean density of hoppers in bands was 15 per sq. yd. There was a tendency for such bands to become larger by fusion and for the area quite free from locusts to increase slightly but the number of dispersed locusts increased. There would therefore have been no advantage in withholding insecticide control in the hope of attacking denser and more economical targets. Nevertheless, such populations have to be controlled.

In the Red Locust, under the conditions described, it seems probable that the behaviour of the young adults is most important in the formation of dense swarms, while in certain other species but not in the Red Locust, concentrated egg-laying and the behaviour of the hoppers are also important.

Investigations are required on more economical enumeration of patchy gregarious distributions.

During the breeding seasons 1952 to 1955, samples of females of the Red Locust, Nomadacris septemfasciata (Serv.), were caught in the Rukwa Valley, Tanganyika Territory, and the ovaries classified according to egg length. Ovaries designated Class V were those regarded as containing eggs ready for oviposition. Population estimates and rainfall records were also taken.

The data suggested that the eggs in the ovaries develop very rapidly, becoming ready to be laid about seven days after the start of development.

The increase in weight of an individual female during ovary development is related to absolute size, and it was found that, during ovary development, the weight increases by approximately one-half.

The most important factor initiating ovarian development seemed to be a drop in daily maximum temperature to below 36°C. The factors of high humidity and rainfall were of less importance but their influence is not fully understood. The possibility of change in length of day being an important factor in the initiation of ovarian development is discussed.

The limiting factors for the number of egg-pods laid in a season are considered to be the dates of the drop in daily maximum temperature and of the drop or decline in parental population. The date of drop or decline in parental population seemed to be connected with the date of drop in daily maximum temperature.

The percentage of females laying more than one egg-pod was calculated, and the resuJts were found to vary considerably from year to year, although the average of 1 pods per female agreed with past estimates. Also, the average period of 16 days between successive egg-layings agreed with past work.

Drought, during the laying period, seemed to cause the females to retain their ripe eggs.

The evidence tended to confirm the possibility of a Red Locust population being able to increase 100-fold in a single year.

A campaign in New South Wales against flying swarms of the Australian Plague Locust, Chortoicetes terminifera (Wlk.), using Tiger Moth light aircraft, is described. Large rolling swarms of this locust, travelling across the open plains of western New South Wales, are directed in their general south-easterly move ment by natural barriers in such a way that regular migration routes are followed and predictions of swarm movements can be made. Of particular importance are the timber fringes of creeks and rivers which tend to baulk swarms temporarily and it was in such situations that locust swarms proved most susceptible to treatment by a manoeuvrable aircraft.

A technique of drift spraying was developed wherein aircraft were able to operate without ground direction against travelling swarms by spraying at right- angles to the wind direction and by using the main body of the flying locusts for demarcation. Large numbers of short spraying runs were made in rapid succes sion over the most dense portions of the swarm being treated until control was achieved. It was found that the spacing of the runs was not particularly important as long as each was applied to the densest portions of the swarm. The light and relatively slow-moving Tiger Moths proved highly suitable for this work and they were also useful for scouting and keeping track of swarms. Observations made after spraying indicated that the coherent flying swarms treated in the open plains were almost completely eliminated. If, however, swarms were able to reach closely settled or heavily timbered areas they tended to split and disperse and were difficult to treat. The insecticide used was an emulsifiable concentrate containing 7 per cent. γ BHC, which was diluted with diesel oil, and one gallon of liquid containing 5·6 oz. of γ BHC was designed to cover one acre. However, as the campaign progressed, effective use of the spray was probably obtained at less than one gallon per acre, and a total area of 30–37 square miles of dense swarms was treated at a cost of approximately £13,700. There is scope for an improvement in the efficiency of the spraying technique as well as a reduction in some of the major costs in any future campaign.

It was considered that the campaign carried out in the Ivanhoe—Hillston district completely controlled all swarms in the area and protected from invasion valuable farming lands to the south-east. Further spraying operations, in the Jerilderie district, 150 miles away, were less successful, although many mor locusts were killed. The spraying party arrived in the district too late to plah a strategic campaign and some swarms escaped treatment.

It is concluded that the method of aerial drift spraying is capable of wider application in Australia, particularly in areas where problems of distance, popula tion and lack of facilities militate against successful control by ground machinery.

In view of the discovery of several new species and subspecies of Amblypelta (Hemiptera, COREIDAE), some of which are either known to be or else threaten to become of economic importance, a revision of the whole genus has become necessary.

The genus Amblypelta, as defined in the present paper and as known so far, is confined to Australia north of Sydney, the islands between Australia and New Guinea, New Guinea and, to the west, the Kai Is., Timor and Java; the Bismarck Archipelago, the Solomon Islands including Bougainville, Eennell and Bellona; the New Hebrides and New Caledonia. In the present revision of the genus, twelve species and five subspecies are included, of which all but seven species are new to science. Apart from the descriptions of the new species and subspecies, taxonomic notes on the previously known species are given as well as a key to all the species.

The known distribution of each species is stated, and consideration given to the zoogeography of the genus as a whole, and of certain species-groups which can be recognised within the genus.

Evidence is given, based on, field observations and experiments, of damage to fruits of cacao by two species of Amblypelta (A. theobromae Brown in New Guinea and A. cocophaga China in the British Solomon Islands); the nature of the damage is described.

A summary is given of the feeding habits generally, and the effects on the plants attacked, of members of the genus Amblypelta.

Comprehensive lists of the known food-plants of each species of Amblypelta are given.

Successful emergence of examples of Contarinia sp. and associated parasites has been obtained at Rothamsted Experimental Station from midge-infested heads of sorghum received from India (Mysore State) and West Africa (Ghana).

Since typical pre-mating behaviour was observed on all of the few occasions when newly emerged males and females from the two continents were confined together, and actual mating was obtained between a male from Ghana and two females from Mysore in rapid succession, it is concluded that inter-mating will take place under suitable environmental conditions, although in the present series of experiments such conditions were rarely present.

It has not yet been possible to test the fertility of such inter-matings or to prove biologically that the species of Contarinia concerned is the C. sorghicola (Coq.) of Texas, although on morphological grounds there are apparently no reasons for their separation.

Two species of parasites, a Tetrastichus sp. (group of flavovarius, auct.) and Eupelmus popa Gir., were reared from the Indian material, and another species of Tetrastichus (group of flavovarius, auct.) and E. popa were reared from the West African material.

A method of estimating the damage inflicted on the developing fruit of the coconut palm by Pseudotheraptus wayi Brown is needed in order to assess the efficacy of measures for the control of this Coreid. The insect lives in the crown of the palm, populations are small in relation to the damage they cause, the adults take wing readily and the nymphs are agile and secretive. Direct estimation of populations by hand-collection, trapping, the use of knockdown sprays and marking-recapture methods, using paints or radioactive materials, were all unsuccessful, and indirect methods of estimation were therefore studied.

The growth, flowering and fruiting habits of the coconut palm are described. There is a single growing point, at which the leaves are produced in succession. From 12 to 18 inflorescences are formed each year; each is borne in a leaf axil and carries male flowers distally and female flowers proximally; the latter open, and are fertilised, almost together, after all the former have fallen off, and some 3–4½ weeks after the inflorescence has emerged from its spadix. All subsequent stages in the development of the fruiting body are dated from the latter event.

The young nut at first elongates rapidly and in the first six months attains over 80 per cent. of its final length; it is ripe at about a year.

In the absence of damage by insects, from 20 to 80 per cent. of the fruiting bodies are shed as nutlets, 1–2 weeks after fertilisation, the proportion depending on the variety of the palm and being less in those that bear few flowers and large nuts, but very few are shed at any other stage of their development. When an adult or a late-instar nymph of P. wayi feeds upon a developing fruiting body a characteristic lesion develops at the site of the puncture, which is concealed by the calyx, and if the fruiting body is less than three months old at the time (in which case it is locally termed a kidaka, plural vidaka) it is normally shed 4–7 days later. As the nut develops, it becomes less likely to be shed following attack by P. wayi, although the lesion formed may be invaded by fungi or by the weevil, Diocalandra frumenti (F.). Fruiting bodies attacked by the latter insect cease growth but are not shed. Experiments and field observations show that where damage by P. wayi is prevalent, a proportion of the vidaka are shed in the pre-fertilisation stage, even though they show no evidence of attack by the insect. The extent and implications of this phenomenon are not yet understood.

Fallen vidaka rot quickly and those that are found will reflect the damage that was inflicted 7–10 days previously. By collecting a sample of freshly fallen vidaka, removing the calyces and determining the percentage of them that shows damage by P. wayi, a measure is obtained that is termed the Vidaka Damage Rate (V.D.R.). The method advocated is to collect at random and at weekly intervals a sample of at least 100 vidaka per ten acres, excluding any with an overall length exceeding three inches. This size is reached at about 2½ months; older fallen nutlets invariably show damage from P. wayi or other causes. No significant differences have been found between values of the V.D.R. based on such collections and those based on collections from below individual palms, or rows of palms, taken at random. No significant difference was found between vidaka in the pre-fertilisation stage and those in the stage at which normal nutfall occurs as regards the proportion showing damage by P. wayi, and the former are therefore not excluded.

Comparison of the numbers of nymphs of P. wayi found by two trained entomologists at weekly intervals on 12 palms in each of two areas, one of which was treated with an insecticidal spray at monthly intervals and the other left untreated, and the V.D.R. determined a week later in the same area but on a larger sample of palms, showed a curvilinear association between the two quantities; the association between the logarithms of the quantities was linear but the correlation was not quite significant. In more detailed investigations, two 100-acre areas were used, one of which was undergoing insecticidal treatment, and in each a large but variable number of palms (from 100 to over 900) was examined during each week over a period from mid-October 1956 to the end of March 1957 by a team of climbers who had been trained to search for P. wayi. There was less variability in the data from the control than from the treated area; the latter showed a curvilinear relationship between the observed population of nymphs of P. wayi and the V.D.R. from the whole area one week later, but the correlation between the logarithms of the two variables was not significant.

If counts of first- and second-instar nymphs, which cause very little damage, were excluded from the data, together with any week in which no individuals were recorded, and the values of the V.D.R. were computed from that part of the area in which the insects were counted, then, when both variables were converted to logarithms, the transformed data showed a straight-line relationship with a highly significant correlation coefficient of −0·975. The regression equation indicates that where the number of palms that it would be necessary to search in order to find one 3rd- to 5th-instar nymph is 10, 100 or 1,000, the corresponding value of the V.D.R. would be 84, 13 or 2·4, respectively. It is concluded that where the V.D.R. is below 20, the population density giving rise to such a rate of damage is so low that its accurate determination by direct counts is unlikely to be possible.

Data on V.D.R. and yield were collected from a number of experimental plots and control areas; values from the latter were too uniform to give rise to significant correlations, but when a quarterly estimate of the V.D.R. in an experimental area, obtained from the totals of damaged and of undamaged fallen vidaka collected during successive three-month periods, was compared with the figure for yield obtained from harvesting the same area during the corresponding quarter the following year, a linear relationship was found between yield and V.D.R., the coefficient of correlation being significant in each of the five areas considered, and ranging from −0·7 to −0·984, and the values of a and b in the regression equation Y = a + bX, where Y is the yield in nuts per palm per harvesting and- X is the quarterly value of the V.D.R., ranged from 13·65 to 19·8, and −0·141 to −0·287, respectively. It is concluded that the V.D.R. is a good measure of expected yield, provided that the rate does not rise unduly in the interval between assessment and harvest; in such circumstances, the increased population of P. wayi that is reflected in the increased V.D.R. may damage the nuts at a later stage of their development and so reduce the yield below that expected.

A technique is described for counting the numbers of Pseudotheraptus wayi Brown on coconut palms, on which this Coreid is a serious pest in East Africa, Zanzibar and the neighbouring islands. The crown of each palm is systematically searched by an African assistant, the insects collected being classified by instars and then replaced. The adults can fly and very few are seen or captured.

Palms were examined by a team of searchers in five areas in a well-maintained plantation on Mafia Island, 3–4 separate samples, each of 61–138 palms, being taken in each area between mid-January and mid-February 1956. In all, 13 searchers participated, but not all were used on the same day; when they had become experienced their daily catches were of comparable size.

The total nymphal populations, and the proportions of them in the various stages, are sufficiently consistent to suggest that the searching technique may give reproducible results, and thus be of considerable value as a means of assessing the results of control measures.

The average catch was about one nymph for each palm that was searched, and recaptures from known numbers of bugs liberated indicated that about one quarter of the population present was being found. The nymphal population is not distributed at random among the palms.

The Cowpea Weevil, Callosobruchus chinensis (L.), has been distributed by commerce and now breeds throughout most of the tropics and sub-tropics, although in the southern part of Africa it is replaced by C. rhodesianus (Pic). The systematics of both species are discussed and redescriptions given of them and of C. subinnotatus (Pic), formerly regarded as a variety of Bruchus vicinus Gylh., together with an account of the genitalia of both sexes, and Tables distinguishing the first two species from one another and the third from the closely related species, C. maculatus (F.).

In an intensive study, begun in 1955, on the biological control of Pseudaulacaspis pentagona (Targ.) and Pulvinaria psidii Mask. on oleander (Nerium oleander) in Bermuda, several species of COCCINELLIDAE were successfully established, but none developed a population sufficient to control either scale. The failure of these apparently suitable species of Coccinellids was therefore investigated. It seemed possible that insectivorous lizards, which are very abundant everywhere, might be responsible.

Dissection of a number of lizards, Anolis grahami, and A. leachi, in the autumn and winter indicated that at both these times their effect on the natural enemies of scale insects in general and of Pseudaulacaspis pentagona and Pulvinaria psidii in particular, was considerable. Both Coccinellids and Hymenopterous parasites were eaten in large numbers. A surprising number of very small insects including ants, was eaten, and although a number of the insects eaten are harmful, on balance it would appear that, particularly with regard to the biological control of scale insects, the elimination from Bermuda of these lizards, which are introduced species, would be beneficial.

Experiments are being carried out to test this, and the introduction of predacious birds, particularly that of the Trinidad kiskadee, Pitangus sulphuratus, is planned.

An examination was made of the movements of Pscudococcus njalensis Laing, the dominant vector of swollen-shoot disease, on cacao in Ghana. The mobile population is composed almost entirely of first-instar nymphs (92%). Movement is initiated at about 23·5°C. and activity becomes more pronounced at higher temperatures. Movement is maximal during mid-afternoon when many hundreds of insects become mobile on heavily infested trees. The density of mobile mealybugs increases from the base of the trunk and reaches a maximum at a few feet below the top of the canopy. Under experimental conditions, nymphs walked at least 28 ft. in search of favourable feeding sites and their dispersion increased proportionately with the number of canopy bridges. On cacao, adults are occasionally carried by the ant, Crematogaster striatula, Emery.

Using insects labelled with radioactive phosphorus, the assumption was confirmed that P. njalensis is capable of walking from tree to tree via the canopies of farmers' cacao. In a plantation of 8-year-old Amelonado cacao, 40 per cent, of the branches were in contact at 4-ft. spacing and about 20 per cent, at spacings between 5 and 7½ ft. No branches were in contact where the trees were spaced more than 12 ft. apart. At the closest spacing, the ratio between the number of mobile mealybugs that reached adjacent contact trees and those that did not was about 9:100, this ratio being reduced to 1 or 2:100 amongst trees growing 5 to 7½ ft. apart.

The significance of the movement of mealybugs in the canopy in relation to virus spread is emphasised. Methods of preventing vector dispersal by pruning, wide spacing and interplanting with a secondary tree crop are discussed. The importance of a closed canopy in preventing attack on the trees by Miridae is stressed.