An Ichneumonid, reared from egg-masses of weevils (Entypotrachelus meyeri Kolbe and E. micans Hust.) harmful to tea culture in Kenya, is placed taxonomically and is described under the name Sozites kerichoensis.

Light-trap catches of Heliothis armigera (Hb.) reach peaks during the wet seasons, April and November–January. Initial infestation of seed beans by H. armigera occurs in April–May at the time of flowering of the early-sown crop, the adults probably originating from an earlier generation on maize. Two generations are completed during the main seed bean season, the first on early-sown beans and the second on later beans, and the dry period July–October may be passed in pupal diapause. Damage, caused by the older larvae eating the seeds in the pod, is prevented by spraying the young larvae with DDT (25% e.c. at 3 pt/2 gal spray/acre) (the standard treatment) or endosulfan (35% e.c. at 1½ pt/2 gal spray/acre) at about six weeks after the beans emerge.

Adults of the Pentatomid Nezara viridula (L.) invade bean fields from alternative host-plants at the same time as H. armigera. This species, even in small numbers, causes the loss of young pods and also damages or kills the developing seed. It is not controlled by the standard DDT treatment for H. armigera, but the following insecticides were found to be effective: γBHC 20% e.c. (1¼ pt), dieldrin 18% e.c. (2 pt) and endosulfan 35% e.c. (1½ pt) in 2 gal spray/acre. Where N. viridula and H. armigera are found together, the standard recommendation is endosulfan 35% e.c. (1½ pt/2 gal spray/acre).

The Coreids Acanthomia horrida (Germ.) and A. tomentosicollis (Stål) cause damage similar to that of N. viridula, but are serious only when infestations are heavy. They were found to be controlled by DDT, dieldrin or endosulfan at the rates given above.

Alatae of the bean aphis Aphis fabae Scop, invade bean fields mainly during the first two weeks of the crop, producing apterae which concentrate on the tip of the plants. Damage (stunting, and loss of flowers and pods) is serious only when large populations of apterae are produced on a high proportion of the young plants. The early infestation demands control measures separate from those for the other pests, the most effective being methyl-demeton 50% e.c. (½ pt/2 gal spray/acre) applied 3–4 weeks after emergence. Endosulfan, although promising and far less toxic than methyl-demeton to larvae of the predator Cheilomenes lunata (F.), was discarded on grounds of cost, as was dimethoate. Aphid populations reached a peak during July and August and decreased with the warmer weather in September. A large number of alternative host-plants is listed, but the source of the primary flight into beans is not known.

Melanagromyza phaseoli (Tryon), the life-cycle of which is completed in 23 days, is unimportant on seed beans as it is least abundant during the growing period of the main crop, but may damage plants suffering from water stress. Tunnelling in stems by larvae was controlled by seed dressings of aldrin or heptachlor (both 40% wettable powders mixed with seed at 1:200 w/w).

This paper is concerned with certain Mymaridae from crop pests in the Far East and the Ethiopian region. Anneckia oophaga gen. et sp.n. was reared from eggs of Sexava in New Guinea, and a key is given for the separation of the genus from other members of the tribe Anagrini. Acanthomymar nigrum gen. et sp.n. is associated with pests of coffee in Uganda and the genus is placed close to Chaetomymar Ogloblin (tribe Mymarini). Gonatocerus brevifuniculatus sp.n. reared from an unidentified scale on Albizia sp. in Pakistan and from Indonesia, Polynema oophaga sp.n. from Tettigoniid eggs in Malaysia, and the previously unknown male of Platypatasson fransseni Ogloblin are described. The original description of Erythmelus helopeltidis Gahan is extended by means of illustrations and Ophiomyia lantanae (Froggatt) is cited as an additional host record. Identification of material from Tanganyika showed the range of Chaetomymar lepidum Annecke & Doutt to extend to that country.

The identity of the Lymantria species in the north-western Himalayas is confirmed as L. obfuscata Wlk., and not as L. dispar (L.) with which it has commonly been confused in the past. The larval and imaginal characters separating the two species are described and illustrated.

Laboratory and field cage trials were made with male Glossina morsitans orientalis Vanderplank treated with tepa or gamma irradiation to assess the ability of the sterile males to compete with untreated males for normal females when the ratios of treated males to untreated males to untreated females ranged from 4:1:5 to 5:2:5. Irradiation of the pupal and adult stages with 8000 and 15000 rad or 8000 and 12000 rad, respectively, reduced reproduction by 87–100% (mean, 95%). Contact for 60 min on a glass surface coated with 10 mg tepa/ft2 or exposure to 0·25 ml of 5% tepa in a wind tunnel usually produced complete sterility (mean, 99%) in 0- or 2-day-old male flies. Trials in the laboratory and in a small field cage (288 ft2) with chemosterilised flies generally reduced reproduction to near the expected values. Similar results were obtained with male flies emerging from irradiated puparia, but males treated as adults produced somewhat smaller reductions than expected. Unreplicated competitive trials with chemosterilised and irradiated males in a large field cage (8100 ft2) produced considerably smaller reductions in reproduction than expected, suggesting that treated males released in nature might not compete for normal females as readily as untreated males.

Three egg parasites, Sozites kerichoensis Kerrich (Ichneumonidae), Oligositoides semicinctium De Santis (Trichogrammatidae), and Platystasius benjamini Nixon (Scelionidae) were reared from egg-masses of two closely related Entypotrachelus species indigenous in the tropical rain forest of Kenya. E. meyeri Kolbe occurs west of the Rift Valley, and E. micans Hust. occurs in the foot-hills south and west of Mt. Kenya, east of the Rift Valley. When the forests are cleared, both species transfer from forest trees, weeds and shrubs to newly planted tea and Cinchona spp. where the larvae feed on the roots and the adults feed and oviposit on the leaves.

Experiments were carried out to remove existing doubts about the toxicity (and therefore cost per unit killing power) of malathion to adults of Schistocerca gregaria (Forsk.) which have arisen from earlier field and laboratory tests. Malathion is shown to be almost as toxic to these insects as γ-BHC, but superior in speed of action. These observations are in agreement with the performance of these two compounds in the field.

Subdivision of a dose of malathion with simultaneous application at two loci increased its toxicity. This, as well as other factors, brings the value of LD50 determinations into question. Recommendations for large-scale use of new insectsicides, based only on laboratory data, may not always be reliable.

Contarinia coffeae sp.n. is described from specimens reared from Coffea arabica in Uganda, and brief notes are given on symptoms, biology, crop loss and distribution. The larvae develop inside young coffee berries. Blister-like external swellings appear on infested berries and they later rot. The pest is known only from arabica coffee in parts of Western Uganda but may be spreading and could appear in other East and Central African countries.

Despite strict standardisation of cultural and bioassay procedures, significant results were attained with difficulty because of great variation in mortalities of batches of adult Ptinus tectus Boield. exposed to insecticide deposits. In tests using lindane, the variation between weekly batches was reduced by selecting beetles within the weight range 1·8–2·4 mg, but variation between replicates in a batch was unaffected. This latter variation was found to stem both from the weights and from the sexes of the beetles; in general, heavier beetles were less susceptible than lighter ones and females were less susceptible than males at comparable weights.

Laboratory and field studies were made to study the flight behaviour and development of thoracic musculature in male Glossina morsitans orientalis Vanderplank collected as adults near Kariba, Rhodesia, or emerged from puparia collected there. Muscular development, measured as thoracic residual dry weight, was significantly inhibited by confinement in the laboratory and flight activity declined when laboratory-emerged flies were maintained in the laboratory. Survival of laboratory-emerged flies in the field was only 17% that of field-emerged flies. Irreversible behavioural and physiological inhibition in flight and in flight musculature is therefore believed to occur within the first few hours of adult life as a result of confinement; 70–80% of the confined population was affected. These inhibitions can be avoided by using field-emerged adults for field trials.

Grain losses per unit area in oats following shoot attack by frit fly (Oscinella frit (L.)) were assessed in plots at Rothamsted. Individual plants were marked, and two categories of attacked plants (tillers and both main shoot plus tillers attacked) were distinguished because losses in the former were low or negligible compared with those in the latter. There was no evidence of compensatory growth for lost or damaged plants, so that losses could be assessed by comparing actual yield with yield expected had no plants been attacked. The percentage loss, weighted according to incidence and effect of attack in the two categories, was calculated from hand-harvested samples. The loss per unit area was then estimated from the actual yield obtained by combineharvesting. Estimates of actual yield were affected by the method of harvesting, so that estimates of loss were not precise.

New evidence on the nature of recession populations of the desert locust, Schistocerca gregaria (Forsk.), and on the nature and role of its outbreaks is presented. It is shown that the hopper bands and swarms reported during the 1963–67 recession differed qualitatively and quantitatively from those characteristic of plague periods and were numerically much smaller than some low density non-swarming populations. Gregarisation frequently occurs in the latter and may be on a scale sufficient to give rise to an outbreak; in turn outbreaks may lead to plague upsurges.

Pediobius furvus (Gah.) (Eulophidae) is a parasite of the pupae of Pyralid and Noctuid stem-borers on graminaceous crops in Africa between 17°N and 17°S. It co-exists with the other pupal parasites Dentichasmias busseolae Heinr. and Procerochasmias nigromaculatus (Cam.) (Ichneumonidae) and Hyperchalcidia soudanensis Steffan (Chalcididae), but it is more abundant below 4000 ft where P. nigromaculatus does not occur. Mating follows a courtship dance, and oviposition occurs in any part of the host pupa. The life-cycle is completed in 18–20 days at 30°C, and up to several hundred adults may emerge from a single host pupa, the most suitable pupae being 2–3 days old at the time of oviposition. Longevity was improved when sucrose was provided as food. Host pupae outside the stem were parasitised, but puparia of Diptera and cocoons of Apanteles sesamiae Cam. (Braconidae) were not parasitised in the laboratory. Pupae formed inside cocoons were not attacked. Pediobius furvus has become established in Madagascar on Sesamia calamistis Hmps, and is considered promising for biological control of graminaceous stem-borers in other countries.

A species of Dioryctria reared from Pinus kesiya (= khasya) at Shillong, Assam, where it is found in association with D. abietella (Schiff.) and D. sylvestrella (Ratz.), is described as new and is named D. castanea sp.n. The distinctive purplish or reddish chestnut brown coloration of the forewings is considered to distinguish this species from others in the genus. Illustrations are given of the adult and of the male and female genitalia.

A species of Gelechiid moth bred from larvae living in galls on the leaves of an unidentified species of Eugenia in New Ireland is described as new and is named Idiophantis eugeniae sp. n. The species is differentiated from I. chiridota Meyr., to which it is closely related and which occurs in the Indo-Malayan region. Illustrations are given of the adult male and the genitalia of both sexes.

A description is given of an artificial stream for studying pupation times and pupal periods of Simulium spp., of emergence traps for studying emergence times in rivers, and of a convenient arrangement for rearing batches of pupae in the laboratory.

S. damnosum Theo., S. kenyae De Meillon and S. unicornutum Pomeroy pupate mainly by day, each species having a characteristic period of peak pupation.

In S. damnosum and S. kenyae the time of pupation influences the pupal period, and for these and other species the pupal period is prolonged by lower temperatures. The pupal period is partly independent of these influences in so far as emergence by night is normally avoided.

The timing of adult eclosion is influenced by the temperature on the day of eclosion. On warm days (midday temperature of the river 24·1–28°C) S. damnosum and other forest zone species show a peak of emergence between 06.00 and 09.00 h, while on cool days (midday temperature of the river 20·1–24°C) the peak is delayed until 09.00 to 12.00 h. On artificially cold days (refrigerator temperature 16–20°C), the peak is shifted to the late afternoon.

The study of the timing of adult eclosion from pupae brought into the laboratory is complicated by the fact that the normal pattern of emergence is liable to disturbance.

In the laboratory a seasonal fluctuation in the sex ratio of emerging flies occurred in S. damnosum.

Descriptions are given of six hypogeic mealybugs forming the genus Geococcus. A key to species and illustrations of five species are included. G. johorensis is described as new from Malaya where it is reported as damaging oil palms. Another new species, G. lawrencei, is described from the Solomon Islands. The history of G. coffeae Green is discussed together with its present distribution.

Laboratory and field investigations into sex attraction and mating behaviour of Glossina morsitans orientalis Vanderplank have been described. Male flies were not attracted to volatile and soluble compounds from two- to three-day-old mature virgin females, or to virgin females in a simple olfactometer. Removal of antennae from either sex did not appreciably reduce insemination rates after 24–48-h mating periods compared with normal flies. Similar numbers of wild male flies were caught off oxen baited or non-baited with mature virgin females. G. m. orientalis probably does not produce a pheromone.

Male flies appeared to be sexually activated only after movement by the female. Mating success was reduced in the dark and when the male's eyes were painted, but blinding the female fly did not reduce insemination. Mating was similar with or without wings and halteres and the sounds produced by them.

Time between pairing the sexes and the start of mating tended to increase, and the percentage of inseminated females accepting two or more matings decreased, after the first copulation. Female flies rarely re-mated within a day. Virgin female flies accepted males passively with partly open wings, and mated females rejected further copulation with closed wings, activity to shake the male off, and primarily a downward-curved abdomen. Virgin female flies mated for periods of 1–45 min did not receive sperm but successful ad libitum mating was reduced a day later. Insemination rates decreased with females older than seven days and reached zero 28–83 days after eclosion, while 37-day-old males inseminated 93% of young females.

Experiments in the glasshouse have confirmed that spraying virus-source leaves or test plants with mineral oil (liquid paraffin) inhibits transmission of beet yellows virus (BYV) to sugar-beet by Myzus persicae (Sulz.). Spraying M. persicae with oil after feeding on BYV-infected leaves and before transfer to virus-free beet seedlings also inhibited their transmission of BYV. The appearance of systemic symptoms of BYV was not delayed by treatment of the test plants or the aphids with oil. The effects of oil on virus transmission were reflected in adverse effects of oil on the settling behaviour and larviposition of the vector on test plants. It is suggested that coating the stylets with oil inhibits the feeding of aphids in the phloem thereby decreasing the efficiency of BYV transmission. The effects of oil on aphid settling and larviposition suggest that spraying crops with oil may not only reduce the incidence of aphid-transmitted viruses in them but may also diminish the population of potential vectors present in them.

Female Musca vetustissima Wlk. may be allocated to one of seventeen classes of development between emergence and the start of the fourth ovarian cycle, the criteria being the amount of pupal fat body, but chiefly the presence and size of the follicular relics (yellow bodies and beads in the ovaries) during successive ovarian cycles. The duration of these cycles was estimated under standard and differing environmental conditions. Withholding protein for up to two weeks merely delayed the first ovarian cycle, but longer deprivation caused reduced fertility. The initial phase of the first ovarian cycle was independent of protein feeding, but a protein feed was necessary to complete the cycle, and a further protein feed was needed to complete the second ovarian cycle. No development in the first cycle took place below 57°F, but between 58 and 78°F development was progressively faster. Unfertilised females developed and laid the first batch of eggs, but were unable to complete a second batch. Oviposition was delayed by lack of favourable sites, and after one week fertility was progressively reduced. It is shown that, because of these variables, valid estimates can be made only of the minimum age of female bushflies.