Larvae of Arenipses sabella Hmps., a serious pest of date palm trees in Israel, developed normally on inflorescences, immature or ripe rates and on green fruits of Phoenix canariensis, and their development at 30°C. took 34–45 days. Survival of males and fertilised famales was 10.8–12.0 days at 25°C. and 7.0–8.2 days at 27°C. No difference was found between survival of males and females, but unfertilised females lived rather longer than fertilised famales. The total production of eggs per female was 285 eggs at 25°C. and 328 at 27°C. At 25°C. 825 per cent. of the eggs were laid during the sixth and seventh nights of the female’s life, at 27°C. 74 per cent. were laid during the third and fourth nights. The total number of eggs laid by unfertilised females was lower than that of fertilised ones. The number of females fertilised was dependent on the number of males present in the rearing cage.

In Israel, only two generations of A. sabella— those in the spring and in the late autumn—become sufficiently large to be of economic importance. Damage occurs during only a short period in spring, when inflorescences, toung fruits and fruit stalks are attacked. In autumn and winter most larvae enter diapause. In the laboratory, the moth passes through four generations a year and even at the relatively high temperatures maintained during the winter the larvae entered a diapause.

Cadra figulilella (Gregson) is a serious pest of ripening dates in Israel and damages fruit still on the tree and also after it has been picked, if it is not then fumigated.

The time taken for development at 30°C. was 54–65 days. At this temperature adults lived for 4–6 days and the average number of eggs laid per fertilised female was 160. Unfertilised females laid fewer eggs. Most of the eggs were laid during the second and third nights after emergence of the female. The number of fertilised females depended on the number of males present in the rearing cage.

A few larvae were observed in the plantation in dropped, decaying dates throughout the year, but attack on the bunches started only when the fruit began to ripen.

Azinophos-methyl (E.C.20%) 0.5 per cent. and diazinon (E.C.25%) 0.5 per cent. were the most effective of the compounds tested. Application when the colour of the fruit began to change and again three or four weeks later resulted in excellent control of the pset.

An account is given of the life-history of Agrilus acutus (Thnb.) (Buprestidae), a pest of ‘mesta’ (Hibiscus cannabinus) in india. The eggs are ovate and scale like, and are laid singly on the stem, usually near a leaf scar, and when kept at 31°C. and 73 per cent. relative humidity hatched on average in 12.4 days. The larva bores through the lower surface of the egg directly into the stem and feeds under the bark forming a sprial tunnel. A raised weal develops on the surface of the stem overlying the tunnel. Before each moult, the larva bores into the wood and makes a vertical chamber in which moulting occurs. There are normally three moults in the active feeding stages, but exceptionally four, and a prepupal moult. The rate of tunnelling is at first about 56 mm. per day and later eaches about 107 mm. The larval stage lests 26 days. The fully grown larva is 21 mm. long and bores into the wood to pupate, making a pupal chamber 11 mm. long into which it fits itself by adopting an asymmetrical U-shaped posture. After a prepupal stage of 2.5 days it pupates. The pupal period occupies about 11.7 days and a further seven days are spent by the adult in the pupal chamber. The adult female mates within a day of emergence from the stem. but does not oviposit until at least seven days have elapsed.

In an attempt made in 1966 to reduce the tsetse fly population in an experiment area of eight square miles in northern Tanganyika to a density low enough to permit safe settlement, undiluted technical fenthion (95% active ingredient) was applied three times at three-week intervals at 0.0041 gal. per acre from a Cassna 185 aircraft fitted with rotary atomisers. The total cost was £95 per sq. mile. Catches in the four weeks immediately following treatment on a flyround of 23,500 yd. sampling the area showed a reduction of over 90 per cent. when compared with those in the four weeks preceding treatment in the case of Glossina swynnertoni Aust. and G. pallidipes Aust. Five months after spraying, the reduction of the former species still exceeded 80 per cent, and that of the latter, 90 per cent. The reduction was smaller in G. morsitans Westw., the most numerous species; a fourth application would probably have improved the kill. The results are compared with those of an earlier experiment in the same area using endosulfan. Some settlement took place in the part of the area where G. swynnertoni predominated.

No method has so far been available for the laboratory culture of Pachydiplosis oryzae Wood-Mason or for the controlled infestation of rice plants with this pest. Suitable techniques for the above have been developed and are described.

For the laboratory culture of P. oryzae, exposure of rice seedlings to gravid females for oviposition and the subsequent maintenance of the plants at a very high humidity in a mist chamber gave high infestation rates but results were not consistent. But this method is suitable for the maintenance of a laboratory culture of this insect.

A special oviposition tube was developed for inducing oviposition on limited areas of muslin, and this permitted easy observation, collection and handling of eggs.

It was found that oviposition tended to occur most frequently between 1900 and 2200 hr. and that the midges most commonly laid 200–285 eggs.

Eggs developed normally and hatched after seventy-two hours when the muslin carrying them was kept on barely moist filter paper in petri dishes.

Sixty-hour-old eggs could be stored for up to five days at 80 ± 2°C. with the percentage hatch decreasing gradually from the first to the fifth day. Low temperature affected development and hatching of thirty-six-hour-old eggs more severely, and hatching was completely inhibited if eggs of this age were exposed to this low temperature for more than two days. Hatching was normal when eggs were maintained at relative humidities of and above 88.8 per cent., but below this level some eggs collapsed as a result of desiccation. At relative humidities below 94.8 per cent., larval movement was initially limited and thereafter inhibited and the larvae were contracted. Such larvae resumed normal activity on immersion in water. These immobilised larvae, obtained by exposure of fully developed eggs to a relative humidity in the range 92.9–94.8 per cent., could be revived by immersion in water and used for infesting paddy plants.

Fully developed eggs, freshly hatched larvae and larvae subjected to relative humidities in the range 92.9–94.8 per cent. and subsequently revived, were transferred to rica plants bt spraying, or by pipetting on the leaf at the ligules or by pipetting on to the soil at the bases of plants. All these mathods proved successful but pipetting on to the soil between rows of plants was the simplest and is to be preferred for controlled infestation of plants.

A very high relative humidity and wet plant surfaces as obtained in the mist chamber used in these studies were essential for successful infestation of rice plants by the gall midge larvae.

Detailed descriptions are given of the adults, larvae and pupae of Mallophora media sp.n., Asilidae, which occurs in Trinidad, W.I. The larvae live in the soil and prey upon larvae of Scarabaeidae. The affinities of the new species are discussed.

Field trials were conducted to compare toxicity and residual activity on cattle of 18 acaricides against Rhipicephalus appendiculatus Neum., Amblyomma variegatum (F.), and Boophilus decoloratus (Koch). Ticks were counted one, four and seven days after the cattle were sprayed. Each of the seven experiments involved three sprayings at seven- to eight-day intervals.

Toxaphene at 0.25 per cent., included as a standard, was relatively slow acting compared to organophosphorous and carbamate acaricides, but was equal to or better than most of the new acaricides in residual activity and over-all effectiveness. Carbaryl, Mopham and toxaphene were tested at the highest concertration, 0.5 per cent., and found to have the maximum over-all effectiveness, including maximum residual activity. Nevertheless, even these treatments did not protexct cattle against tick attachment and engorgement for as long as seven days.

All acaricides tested were very effective against B. decoloratus and A. variegatum, but none completely prevented attachment of R. appendiculatus foe as long as four days, even though all were very toxic to this tick. The smallest number (1.8 per beast) of R. appendiculatus attaching in four days occurred on the cattle sprayed with 0.5 per cent. carbaryl, but by seven days after spraying there were many ticks attached and some were already partially engorged. The inference is that none of the compounds tested gave promise of prevention of tick-borne disease transmission when used on a seven-day schedule. No inference is made concerning tick-borne disease control by reduction of tick numbers on the pasture land.

Mortality among ticks on the cattle one day after treatment was greatest for 0.1 per cent. coumaphos, 0.25 per cent. Prolate, 0.05 per cent. Bayer 9053, 0.2 per cent. Geigy GS 13006, 0.2 per cent. and 0.5 percent. carbaryl, 0.1 per cent dioxathion, 0.05 per cent. Bayer 9037, 0.1 per cent. prothidathion, 0.1 per cent. Dursban, 0.2 per cent. and 0.5 per cent. Mobam, 0.025 per cent. and 0.05 percent. chlorfenvinphos, 0.2 per cent. fenitrithion and 0.1 per cent. ethion. Mortalities of 83.1 per cent. to 88.5 per cent. were given by 0.05 per cent. diazinon, 0.1 per cent. bromophos-ethyl, 0.025 per cent. Dursban, and 0.5 per cent. toxaphene. Mortality below 74 per cent. was caused by 0.25 per cent. toxaphene, 0.2 per cent. bromocyelen, and 0.1 per cent. carbophenothion.

Experiments were conducted to ascertain whether the rearing density of Dysdercus fasciatus Sign. affected its rate of development, colour, size, reproduction and general activity. The length of the nymphal and adult life decreased when more than 12 insects were reared per 200-cc. cage. Isolated virgin females and females that eopulated once lived longer than females each kept constantly with one male. Nymphal crowding in adults that were smaller than those reared in isolation and in an excess of males. Nympha derived from crowded parents became red at an earlier age than the progeny of one male and one female per cage. Crowding reduced feeundity when the density of nymphs or adults, either male or female, was increased.

The pre-oviposition period and the time interval between successive egg-batches were greater for virgin than for mated females. Infertile eggs were the longest; females allowed to copulate once laid eggs intermediate in size between infertile ones and those laid by females each kept with a male. The number of eggs laid by females isolated throughout life with one male was found to be higher than the number laid by those that were crowded either in the nymphal stages or were crowded with males in the adult stage. When Dysdercu8 was crowded with one or two locusts the number of eggs laid and the number of egg-batches were considerably reduced; amputation or painting the antennae, which caused the Dysdercus to be less active, also reduced egg production but disturbance by mechanical shaking of the container had little effect. These findings are discussed in relation to the ' phases ' of locusts and other insects, and it is concluded that the effects of crowding on D. fasciatus do not completely parallel phase differences in locusts.

Puparia of Glossina morsitans Westw. were collected in the Zambesi valley and contained developmental stages from final phases of third-instar larvae to pupae near to eclosion. These puparia or the emerging adults were exposed to gamma-radiation from a Co60 source at rates between 54 and 122 rad/min. Effective mortality in the pupal stage increased from 23 per cent, at 2,000 rads to 64 per cent, at 15,000 rads, while those deposited in spring (August-October) were more sensitive to gamma-rays than those collected in winter (May-July).

Under described test conditions, 25 pairs of untreated flies produced a mean of 21 pupae in a 28-day test period, insemination averaged 95 per cent., and 56 and 62 per cent, of the males and females survived, respectively. Continuous irradiation reduced reproduction by over 95 per cent, between 8,000 and 15,000 rads wiih males emerging within the first two weeks after treatment; while males emerging during the third post-treatment week were completely sterilised with dosages above 4,000 rads. Treatments given as fractions one and four days apart gave a slightly higher level of residual fertility than that obtained with similar but continuous total dosages. Irradiation of adult males reduced reproduction to an extent comparable with that observed in males emerging from pupae within two weeks of treatment (> 90 per cent, from 8,000 rads). Females treated either as adults or as pupae were completely sterilised with doses of 1,000 to 8,000 rads. Males exposed to 8,000 and 12,000 rads retained their sterility throughout 39- and 45-day test periods, and were fully competitive with untreated males.

Survival of virgin flies emerging from treated pupae was reduced both by increasing dosage from 4,000 to 15,000 rads, and decreasing pupal age at the time of treatment. Mortality during the 28-day mating period decreased with 1,000 and 2,000 rads, increased up to 8,000 rads, and apparently decreased with 12,000 and 15,000 rads. When the doses were fractionated, survival was longer than when treatment was continuous, and mortality was reduced to the level expected from the size of the first fraction. Virgin adult males given doses between 4,000 and 18,000 rads, and females given 2,000 and 4,000 rads, lived longer than the corresponding controls.

The ability of the males to inseminate females was not affected by any of the treatments, and sperm from irradiated males were mobile and apparently behaved normally. Dominant lethality in the males was expressed by the failure to produce pupae in matings with untreated females, and in the treated female fly by the complete failure of oogenesis.

Earias biplaga Wlk. has been recorded to attack Theobroma cacao from the Ivory Coast to the Congo (Léopoldville) and also in San Thomé and is the only species of the genus to do so in Africa. Attack is most serious on seedlings in the field as the apical buds are destroyed.

Eggs are laid on the stem mainly, especially on leaf bracts. The first half of the larval period is passed within the apical bud and the last half in feeding on unhardened flush leaves, or, in their absence, in burrowing down the stem below the apex or in devouring the epidermis of the upper stem.

The length of the larval and pupal periods is inversely related to the mean maximum temperature; they are shortest in the dry season and longest in the wet season.

Differences between the sexes exist in the wing coloration, and in the shape of the labial palps, the last segment of which is much longer in the female than in the male. The dry-season form, which has the forewings suffused with golden brown in the female and with yellow-green in the male, instead of the wet-season green, occurs from January to March in the region of Ibadan, Western Nigeria.

The adults are largely nocturnal and they are attracted to ultra-violet light.

Adults lived longer in the laboratory on a diet of sucrose in water (males, on average, 17 days and females, 28 days) than on water alone or without either. A mean of 95 eggs per female was recorded from sucrose-fed adults in the laboratory and the greatest number of eggs laid by a single female was 461. The peak period of oviposition was the fourth to fifth day after mating (fifth to sixth after emergence). A method of rearing E. biplaga in the laboratory is described.

Six alternative host-plants in Nigeria, all in the Malvales, are listed, and one, Hibiscus esculentus, is a locally important food crop. Nine Hymenopterous parasites were found to attack E. biplaga in Western Nigeria, the most important being Trichogramma luteum (Gir.) which attacks the eggs, destroying over 90 per cent, of them at certain times of the year. All the other parasites, with one possible exception, appeared to attack only the larval stage of the host.

The distribution and trypanosome infection rates of Glossina morsitans submorsitans Newst. were studied during the wet season of 1967 along 75 miles of the main trade cattle route which passes through the savannah country between Ilorin and Oyo in south-western Nigeria.

G.m. submorsitans was found inhabiting open woodland, grassland, farmland and the environs of towns associated with the cattle route. In comparison with the types of habitat this species occupies in its zone of wide distribution in northern Nigeria, those habitats studied were considered atypical. It is suggested that the presence of G.m. submorsitans in the area investigated had resulted from a southward population advance over the last 50 years and this hypothesis is discussed in relation to existing knowledge of G.m. submorsitans advances.

The trypanosome infection rates of 61.6 and 76.6 per cent, found in 364 examples of G.m. submorsitans dissected are much higher than previously recorded for any of the subspecies of G. morsitans Westw. A steady southward increase in the trypanosome infection rates of G.m. submorsitans was demonstrated for populations inhabiting 200 miles of cattle route. Trypanosome infections in G.m. submorsitans are attributed to Trypanosoma vivax and T. congolense, and the absence of brucei-group infections is discussed in relation to the incidence of T. brucei infections in trade cattle and limitations of the technique used for demonstrating infections in tsetse flies.

It is stressed that epizootiological aspects of the present findings cannot be clarified until reliable data on trypanosome infections of trade cattle in the area studied are available.

All of the pupae, totalling over 3,750, produced by 320 laboratory-bred females of Glossina austeni Newst. allowed to feed from rabbits’ ears, were weighed soon after deposition. Pupal weights were relatively low initially but increased during the first 30 days of the females’ productive life, were high during the next 100 days or so and thereafter declined to less than the initial level.

A photographic apparatus is described for obtaining a record of oviposition and larval eclosion at intervals through the night. By the use of electronic flash a negative silhouette image is produced and the method used does not appear to disturb the moths during oviposition. A second apparatus incorporating a moving pen is also described for studying and recording the times of emergence of moths from their pupae.

Third-instar larvae of Rhopaea morbillosa Blkb. (Melolonthinae) were maintained at fixed depths between wire-mesh screens in earthenware pots during a 12-week factorial experiment designed to study the relationship between depths of feeding and damage to roots and foliage yield of Lolium perenne and Trifolium repens under two soil-moisture treatments (10% and 20%), with and without fertilisers.

Depth of feeding had a highly significant effect on relative root damage and foliage yield, and at all depths (18, 14, 12, 1, 2, and 4 in.) significantly greater root damage occurred under conditions more favourable for pasture growth.

Ryegrass was deeper rooted and suffered more damage than clover. The degree of non-linearity of root distribution with depth affected damage to roots at all depths so that species in mixed swards should suffer damage in proportion to their deep-rootedness.

It is clear that depth of feeding can confound experimental studies of damage by scarab larvae, and in the field it will influence the damage caused to pastures.

Plagiohammus spinipennis (Thorns.), a native of areas of Central and South America where rainfall exceeds 50 in. per annum, has been imported into Hawaii and Australia for the control of Lantana camara. The larvae girdle a stem of the host-plant and then tunnel extensively in the xylem tissues. In Hawaii multiple infestation of stems over 0-5 in. in thickness was found to be usual. Most attacks were within 25 in. of the ground and stems were killed or so severely weakened that they readily broke off, reducing tall plants to mutilated stumps eventually bearing small regrowth shoots. The life-cycle normally lasts one year.

An annual rainfall of at least 50 in. appears to be necessary for the development of large populations, and the amount that falls before and during the oviposition period influences larval survival. It is concluded that the insect should be very useful as a biological control agent for L. camara.

The content of proline, alanine and glutamate in the thorax of tsetse flies (Glossina morsitans Westw.) caught by two different sampling techniques is compared. Flies caught on a stationary bait animal have significantly less proline and significantly more alanine and glutamate than flies caught on a fly-round. The difference suggests that flies of the bait sample have been more active than flies of the fly-round sample during the period immediately preceding capture.

In an investigation of the fauna of plum at East Mailing Research Station in 1966, over 70 species of the commoner arthropods were listed.

Different species of mite were found to prefer different parts of the tree, different parts of the leaf, and leaves of different ages on a shoot. Aculus fockeui (Nal. & Trt.) (Eriophyidae) was found to spread up the shoots during the early summer and to attain a density of over 100 per sq. cm. of leaf surface. Panonychus ulmi (Koch) was found to be commoner to the east of the tree, and leaf damage that it caused graded in severity across the plot. The species composition of populations of the Phytoseiid mites could differ markedly between trees in the same plot.

A study of the population trends of the commoner species based on numbers per shoot revealed that the populations of aphids and their predators developed two peaks during the season. There was a relatively high incidence of Entomophthora infection on the aphids, and overwintering fungal spores were produced when the aphids died in crevices on the bark, but only short-lived cornidia when they died on the leaves. The population density of member species of the fauna varied considerably, the smallest phytophagous mites reaching levels of 200 per shoot, predacious mites 10.0 per shoot and predatory bugs such as Blepharidopterus angulatus (Fall.) only about 0.01 per shoot.

Analysis of the results obtained from suction-trap catches of the coffee leaf-miners, Leucoptera meyricki Ghesq. and L. caffeina Wshbn. on an unsprayed block of coffee at the Coffee Eesearch Station, Lyamungu, on the slopes of Kilimanjaro, are given.

By thermal summation methods it was possible to delimit successive generations of moths with some degree of accuracy and the generation catches were used for regression analysis with various meteorological factors. With L. meyricki, a negative correlation was shown between the rate of increase from one generation to the next and with both maximum and mean daily temperature, solar radiation and duration of sunshine taken as means over the period of each generation. In each case, the highest degree of correlation was found between the meteorological data in one generation and the rate of increase in the next.

When the generation catches were plotted on a logarithmic scale it was found that linear regression lines could be fitted to the periods of both rise and fall of the annual outbreak. With L. meyricki, the rate of increase of the rise was negatively correlated with, and the rate of decrease of the fall positively correlated with, the size of the generation present at the beginning of the outbreak. It is therefore possible, knowing the size of the minimum generation, to predict the size of the coming outbreak. No such relationship could be proved with L. caffeina, probably because the catches of the key generations were very small, but when the catches of the two species were pooled the same relationship held. It is probable that parasites are the main factor governing the annual fluctuations.

A method for continuously rearing cabbage root fly, Erioischia brassicae (Bch.) is described.

Adult flies fed on sucrose, brewers’ yeast and yeast hydrolysate laid an average of 220 eggs per female when caged together in large numbers and 376 eggs per female when caged singly. Egg viability was 86 per cent. Egg hatch was severely reduced by relative humidities of less than 90 per cent, and the embryo became more susceptible to desiccation as it matured. The larvae were reared on swede, and maximum survival was obtained when the swedes were inoculated with an optimum number of eggs calculated from the ratio of 1 egg: 1.6 g. of swede. Different ratios were obtained from turnip and winter radish indicating that survival was probably related to the nutritional value of the rearing medium as well as to its availability. An average of 68 per cent, of the eggs placed on swede produced pupae that were equivalent in size to wild pupae. The fecundity of the flies was directly related to pupal weight and to the availability of protein in their diet. Adult longevity was reduced more by mutual disturbance than by any other factor.

A new type of olfactometer was designed to study the responses of mosquitos to various stimuli. Hosts could be displayed downwind as well as upwind from the mosquitos, and two hosts could be displayed simultaneously, one upwind from the other. Responses to radiations, if any, and to odours could be measured.

Mosquitos were not attracted downwind to an arm displayed within 61 cm., even when they were stimulated by CO2 (under an incident illumination of about 10 foot-candles). About half the mosquitos showed a positive anemotactic response (i.e., they left the end downwind compartment in which they were released) in a current of room air, which undoubtedly contained human emanations. Only 15 per cent, responded to filtered air. Carbon dioxide caused no increase in response to filtered air but increased the number responding to room air (76 per cent, left the end down-wind compartment). Equal numbers of mosquitos responded to an arm displayed upwind in room air and in filtered air, i.e., about 83 per cent, left the end compartment. Carbon dioxide caused no increase in the number of mosquitos responding to an arm but increased the number responding to attenuated emanations from an arm. A repellent (deet) eliminated most of the response to an arm; the addition of carbon dioxide increased upwind flight to the treated arm, but many of the mosquitos flew past it. Carbon dioxide therefore appears to have a synergistic action with arm odours in the attraction of females of Aedes aegypti (L.). However, this conclusion does not exclude other behavioural effects of carbon dioxide demonstrated by other investigators.

Eesponses to arms in this new type of olfactometer were nearly identical to those obtained in another type previously used in a large-scale study. The testing confirmed earlier reports that mosquitos do not fly far in the same direction as wind-current and that host location was not possible through positive anemotaxis in the absence of light. Mosquitos were not attracted to a source of infra-red radiation.

The new direct method of comparing the attractiveness of different subjects demonstrated that mosquitos would leave the vicinity of one arm and migrate further upwind to another that was more attractive. Water and acetone rinses of human arms reduced attraction; acetone appeared to be a better solvent for the attractant substance than water.

The taxonomic status of the Culex vishnui group of species is discussed. Three species belonging to this group, C. vishnui Theo., C. pseudovishnui Colless and C. tritaeniorhynchus Giles, were recognised in the study area near Vellore, South India. All three species are described on the basis of adults and larvae, and keys for the identification of adults are provided.