Studies were carried out in Jamaica on the larval biology of Leptoconops becquaerti (Kieff.) in 1962–63.

Larvae were reared on natural breeding sites in chambers constructed from large tins, by methods that are described in detail. The features of the breeding sites are illustrated and briefly discussed.

The developmental period from egg hatching to adult emergence probably occupies four to eight weeks, depending to a certain extent upon temperature and hence on time of year. It is unlikely that the adult stage is ever reached in much less than three weeks under natural conditions. Under experimental conditions, overall survival to the adult stage was frequently greater than 20 per cent., and occasionally over 50 per cent. It is considered that survival in natural populations is probably also quite high.

Larval mortality in the experimental chambers apparently occurred maintly in the first instar, and this probably happens in nature. The results showed a relationship between percentage survival and egg number such that proportionately fewer adults were obtained from chambers with greater numbers of eggs. This was interpreted as being due to progressively more severe starvation of very young larvae in the more crowded chambers.

There was no marked tendency for adults of the more same sex to emerge first in the chambers. The sex ratio among the total of 1,039 adults obtained was 1:1.

In an experiment to investigate the diel rhythm of adult emergence, 71 per cent. of adults of L. becquaerti emerged in the four-hour period of 0300–0700 hr., and a further 27 per cent. appered between 0700–1100 hr. This is earlier than found in Culicoides furcns (Poey) in a previous experiment.

The effects of infestation by Contarinia nasturtii (Kieff.) on the growth and yield of swedes were observed in a centric-systematic-area sample consisting of 720 individually tagged plants. Severe infestation by the first generation caused multiple haeding and some reduction of yield, though it was attack by the second generation that more strongly depressed yield. From the results of laboratory experiments described it is inferred that it should be possible to achieve satisfactory control by simple cultural procedures designed to bury the pupal cocoons too deeply in the soil to permit successful emergence of the adult midges.

Laboratory studies were undertaken to find out if the increased degree of infestation by certain moth species, Cadra cautella (Wlk.), plodia interpunctella (Hb.) and Corcyra cephalonica (Stnt.) following the chemical control of beetles including Tribolium castaneum (Hbst.) in stacks of groundnut (Arachis) in Nigeria could be due to relaxation of inter-specific competition.

All test insects were reared and studied at a constant temperature of 25.5°C. and 70 per cent. ralative humidity. All experiments were conducted on shelled nuts (or germs of nuts) in specimen tubes, crystallising dishes or jam jars. The survival and development of the immature stages of the moth species was studied and the numbers of eggs laid by the adults recorded in the presence of adults of T. castaneum; the reciprocal effects of moth larvae on T. castaneum were also briefly studied.

The most important harmful effects of T. castaneum were on copulating moths and on moth eggs. Adults were frequently disturbed and sometimes killed or, if they survived, laid fewer eggs; eggs were also eaten, especially those laid loose in the medium. Adults of T. castaneum also attacked and killed moth larvae and pupae, but this was considered to be of minor importance. The silk produced by moth larvae was inimical to larvae of T. castaneum, but the effect on the population of T. castaneum was probably offset by the beneficial effect of moth cocoons, which provide shelter for larvae of T. castaneum from cannibalism.

It is conculaded that as a result of competition for food and/or space between T. castaneum and the moth species the moth populations are likely to be exterminated despite their apparently higher intrisic rate of increase.

The species of Sesiidae reared from larvae feeding in the vines and tubers of sweet potato (Ipomoea batatas) in Kenya are described as new and named Synanthedon leptosceles and S. dasysceles, respectively. Illustrations are given of the adults and male and female genitalia of both species. S. leptosceles is differentiated from the superficially similar East African species S. erythromma Hmps., which also is associated with sweet potato. Aegeria pyrostoma Meyr. is synonymised under S. erythromma following the examination of type material. S. dasysceles is noted to be readily distinguishable from these and other known species of Synanthedon by the rough scaling and white markings of the legs.

The feeding of Eupteryx melissae Curt. (Cicadellidae) on the leaves of ssge gives rise to the appearance of chlorotic spots, as a result of damaged mesophyll cells becoming filled with air. The length of the mandibular stylets in this species (as averaged from the adult and five nymphal instars) is 67 per cent. of that of the maxillaries, both types of stylet being slightly larger in females. The mandibular stylets when inserted do not penetrate much below the leaf surface where they are held by barbs and a salivary sheath, and the total extent of their insertion is only 29 per cent. of that of the maxillary stylets. The latter are the main penetrating organs; the stylets may move together or independently and are not surrounded by a sheath. Mandibular and maxillary penetration is greatest in fifth-stage nymphs, the mean (and maximum) distances being 97 (205)μ and 177 (340)μ respectively. It increases progressively from the first nymphal stage, and in the adult shows mean values near those of nymphs in the third or fourth stage. Rate and depth of stylet penetration is very variable, due to repeated maxillary protraction and retraction, and there is little correlation between the lengths to which the mandibular and the maxillary stylets are extended. Exuvial stylets, particularly the mandibulars of fifth-stage numphs, consistently show a graeter degree of extruction than is to be found in nymphs when feeding normally: such deeper insertion may help to anchor the insect more firmly during ecdysis.

Stylet insertion is by pressure, intracellular, and very rapid (attaining rates up to 115μ per minute). The sex of the individual insect and the leaf-surface attacked have no effect on depth of penetration, at least in certain nymphal stages, and all tissues of the lamina are available for feeding, even to first-stage nymphs, in consequence of the relatively greater development of the stylets in the younger insects. During penetration the mandibular stylets move alternately and initially lead, but quickly come to rest, and further penetration is by the maxillaries which follow a mainly intracellular path. Protrusion of one maxillary stylet beyond the other (up to a maximum distance of 112μ.) was observed in plant tissue and observations of feeding on stripped epidermis show that such a stylet can empty cells at its apex. Protoplasts are removed from a cell within a few seconds, and as this appears to be too short a time to allow digestion, it is assumed that chloroplasts must be mechanically fragmented on passage into the food canal. Removal may be a two-stage process, and if it is assumed that sometimes only the first stage is completed, and is accompanied by saliva injection, it is possible to explain the occurrence, as unimbibed residue, of plasmolysed degenerating chromophilic cells scattered throughout damaged tissue, which occurs mainly in the palisade and spongy parenchyma, and only seldom in vascular tissue. There is no evidence for diffusion of any salivary toxin from damaged cells or from the sheath. Stylet-tracks in damaged areas are unbranched and short and rarely give any indication of the cells fed upon or of the repeated probing by the maxillary stylets that is known to occur.

Previous attempts to control Woolly Apple Aphid (Eriosoma lanigerum (Hsm.)) in Rhodesia are briefly reviewed. By the application of dimethoate at a rate of more than 5.0 grams a.i. or of vamidothion at more than 6.0 grams a.i. to the soil in the drip area of the tree, it was found that good control of both the foliar and root populations of the insect could be obtained on three-year-old apple trees 10 feet high. and the treatment appeared to remain effective for three seasons. It is considered that the timing of the application, the soil temperature, and the amount of wead cover are all important factors in affecting the amount of insecticide taken up by the apple trees.

In a study of the incidence of damage to coconut palms in Madagascar and the Comores Archipelage caused by species of Oryctes (Scarabaeidae) it was found that attack is heaviest in localities where there are abundant breeding sites for the beetle, and that tall palms are more often attacked than short ones. The most important larval breeding sites are dead standing coconut palms and decaving coconut trunks and stumps. Larvae also breed in decaying satra trunks (Medemia sp.), wood of Albizia in coffee plantations, decaying Raphia trunks, and occasionally in rubbish heaps and manure, but are only rarely encountered in decaying wood in forests. Coconut palms are important feeding sites for O. gigas, O. blucheaui and O. simiar. O. pyrrhus attacks coconut seedlings and young oil palms. Forest palms are occasionally attacked. O. ranavaloattacks bamboo on the east coast. Banana plants are occasionally attacked by O. simiar.

Scoliid parasites of the larvae of Oryctes are widely distributed but not commonly found. Gregarines in larvae are also widespread but of rare occurrence. Oxyurid nematodes were often found in the fermantation chamber at the gut of Oryctes and Cetonid larvae. The fungus Cordyceps sp. was found at only one locality where it was attacking 56 per cent. of the larvae of Oryctes. Examples of infection by the fungus Metarrhizium were rarely encountered. Namatodes often occurred in the aedeagus of adult males of O. gigas and in the bursa copulatrix and colleterial glands of adult females, as well as under the elytra. They were less common in the other species of Oryctes examined. Mermithid nematodes were found in adults of Oryctes on rare occasions. No insect parasites of the adult stage of Oryctes were found. Elaterid larvae, possibly predacious on those of Oryctes were occasionally found but did not appear to be of much importance.

It is concluded that the major factor limiting Oryctes populations in Madagascar and the Comores is the number of suitable breeding sites.

An account is given of Diconocoris hewetti (Dist.), a sporadic pest of pepper in Sarawak. Most of the observations were made during a single outbreak in 1964. The egg and the five nymphal stages are described. The life cycle is completed in about 30 days at 27 ± 1°C., 80 ± 2 per cent. R.H. and the duration of individual stages is as follows: egg, at least ten days; first instar, four days; second instar, three days; third instar, three days; fourth instar, four days; fifth instar, five days; adults in laboratory cultures lived, on average, for 27 days.

Eggs are laid singly in the flowering inflorescences, and nymphs do not generally move far from their hatching sites during nymphal life. Both nymphs and adults feed on the inflorescences and infestation is particularly heavy on those spikes in which fertilisation of the flowers has ocurred but where the developing fruits do not yet exceed 1 or 2 mm. in diameter.

A survey of 60 holdings in the Kuching area showed that numbers of Tingids are very low during non-outbreak periods, only 0.4 individuals per vine (adults and late nymphal instars) being obtained during the flowering season. Numbers deceased to 0.03 insects per vine during the fruiting period. In the outbreak studied, numbers per vine varied from 3 to 10, a ten- to one hundred-fold increase over the normal levels; these figures are relative estimates only as there was no satisfactory method of estimating absolute densities in the time available.

It is suggested that serious outbreaks of Diconocoris may be due to exceptional prolongation of the flowering period of pepper vines in a district, due to cultural practices or climatic factors.

Yield losses due to Tingids in the area studied were estimated at about 30 per cent. Diconocoris can be satisfactorily controlled with sprays of various insecticides including BHC, DDT, malathion, carbaryl (Sevin) and nicotine.

A procedure is described whereby, by the use of appropriate statistical methods, the approximate vertical distribution of the eggs of Aedes vexans (Mg.) in a pool can be ascertained from a relatively few samples taken without any previous knowlwdge of their position.

Myzus persicae (Sulz.) has a wide range of possible host plants in Rhodesia though most may be physiologically unattractive to alate aphids that alight on them during the dry months of the year. Infested plants are difficult to find, yet as many winged aphids are trapped in the dry season (June) as in the wet (December). A wide dispersal of small colonies on a large variety of partially acceptable host plants during the dry season in therefore suggested. Potatoes and other garden plants may contribute to the population but tobacco regrowth is discounted as a source of aphids, though not of viruses.

Seven strains Musca domestica L., including one susceptible strain, were tested with a wide range of organophosphates and carbamates. The results of these tests gave a broader picture of the patterns of cross resistance in strains that had been studied by previous workers and in addition showed two new types of resistance machanism, one possibly and oxidation mechanism, and the other possibly a modified AliE giving low levels of resistance to organophosphates and carbamates. This work also demonstrated the existence of at least three resistance machanisms for carbamates, two probably oxidative and the others minor machanisms associated with modified AliE.

It has been found that the size of adults of the parasites Mutilla glossinae Turner and Thyridanthrax abruptus (Lw.) reared from puparia of Glossina differ with the size of the host, the puparia of the larger tsetse species, G. pallidipes Aust., producing larger parasite than the puparia of the smaller species, G. morsitans Westw. A significant relationship has been found between size of puparium (measured by puparial width) of G. morsitans and size of the parasite (measured by thoracic area and dry weight) for males of T. abruptus and males and females of M. glossinae, and it is suggested that this relationship may extend also to other species of Thyridanthrax and Mutilla that parasitise Glossina. Evidence, both from other workers and this laboratory, indicates that it is the different quantities of food supply in the hosts that affects the size of the adult parasite.

In the course of entomological investigations in Malaya between 1965 and 1967, it was found that Calyptra eustrigata (Hmps.) (Noctuidae) frequently pierces the skin of mammals to feed on blood, and in this respect differs from those Noctuids that marely imbibe blood from an open wound. Other species of Calyptra are known as fruit-piercing moths, and C. minuticornis (Gn.) which was taken in Cambodia on one occasion at the eye of a buffalo, is also one of the eye-frequenting moths, which imbibe lachrymal secretions of Ungulata, Proboscidea and occasionally of man. C. eustrigata has been observed imbibing blood after piercing the skin of buffalo, Sambar deer, Malayan tapir and nilgai antelope. Caged adults in the laboratory were observed piercing the skin of human fingers offered to them; and imbibition of blood continued for up to and hour. The proboscis, which ends in a sclerotised and strongly barbed point, can penetrate about six millimetres below the surface. The two halves of the proboscis work like two paralled saws moving alternately. While feeding is in progress, droplets of saliva exude at the base of the probiscis and run down the outside. Often some blood is regurgitated, then reabsorbed. The puncture causes itching, which can last for up to an hour, and local hardening of the tissue, which can persist for five weeks. By reason of its mode of feeding, C. eustrigata would appear to be a potential vector of disease, as the saliva and regurgitated fluids might transmit pathogenic agents.

The Cercopidae are divided into two subfamilies, Cercopinae and Tomaspidinae, which differ from the concepts to which these names have hitherto been applied, and now include Old World and New World genera, respectively. The former Aphrophorid subfamily Neaeninae is reconstituted as a tripe of Cercopidae, and the tripe Funkhouseriini is suppressed under Tomaspidini. The genera of Tomaspidinae are keyed. and eight, Iphirhina, Aracamunia, Ocoaxo, catrimania, Urubaxia, Tunaima, Tapaiuna and Zuata, together with two subgenera, Zulia (Notozulia) and Mahanarva (Ipiranga), are described as new. One hundred and thirty-six specific names are recombined. Eight names are suppressed in synonymy, and notes are given on the genera in which these changes are made.