The African species of Eurystylus are revised and their status as pests of important agricultural crops is reviewed. A key is provided for the 12 recognized species, one of which, E. lestoni, is described as new. A diagnosis and description are provided for each species, as well as illustrations of diagnostic taxonomic characters and information on host-plant associations and distribution. Lectotype designations are made for eight nominal species of Eurystylus and two species are removed from the genus. The following new synonymies are established: E. annulipes (Poppius)= E. annulipes impunctatus (Poppius), syn. n.; E. bellevoyei (Reuter)= E. parvulus(Reuter), syn. n., E. occidentals Wagner, syn. n., E. gallouedeci Villiers, syn. n. and E. argenticeps Odhiambo, syn. n.; E. lineaticollis Poppius=E. pallidiventris Poppius, syn. n. and E. mutabilis Bergoth, syn. n.; E. oldi Poppius=E. kivuensis Schouteden, syn. n., E. risbeci Schouteden, syn. n., E. phaiopterus Odhiambo, syn. n., E. immaculatus Odhiambo, syn. n. and E. bilqis Linnavuori & Al-Safadi, syn. n. Two species are removed from the genus Eurystylus(E. sobrius (Walker)= Plesiocapsus sobrius (Walker), comb. n. and E. sericeus (Walker)=Proboscidocoris sericeus (Walker), comb. n.) and one species, E. rufocunealis Poppius, is assigned the status of nomen dubium.

A plot of cocoa trees at the Cocoa Research Institute, Tafo, Ghana, was inspected weekly for the presence on each tree of 18 species of insects. The 306 consecutive weekly records of percentage of trees occupied by each species were subjected to time series analysis. Auto-correlation and partial auto-correlation functions were calculated for each series and used to identify simple autoregressive linear models to account for the serial correlation. It was found that all species needed a stabilizing autoregressive parameter of lag 1 and all but four a second autoregressive parameter of lag 2. Seasonal autoregressive parameters at lags 3, 4, 5, 7, 9, or 13 were needed for over half the species, either in addition to the parameter at lag 2 or in place of it. It is postulated that these seasonal parameters mimic generation cycles. Runs of the models using random inputs produced series which were close to the originals in general form. The models could be further refined by adjusting the fixed mean levels assumed by the models to take into account the effects due to the abundance of young extension growth on the trees and atmospheric moisture, as measured by afternoon relative humidity readings. Although the production of extension growth is cyclical it would seem that it does not induce the cyclical behaviour observed in some of the insect series. The peaks in the latter cycles are, however, reinforced when they coincide with peaks in extension growth.

Field trials were conducted in certain eastern counties of England in the years 1957–1959 to assess chemical control methods applied at sowing time against wheat bulb fly, Leptohylemyia coarctata (Fall.). Combine-drilled treatments, using fillers of aluminium silicate, brick dust, granular clay, superphosphate or compound fertiliser, included aldrin at rates from 0·3 to 5·5 lb., dieldrin at 2 and 4 lb., and heptachlor at 2 lb. active ingredient per acre, respectively. Seed-dressing treatments applied with organo-mercury fungicide included 40 and 60 per cent. dieldrin and heptachlor, 40 per cent. aldrin, 60 per cent. Thiodan, 40 per cent. γ BHC with and without organo-mercury, all applied at 2 oz. per bushel of seed; 60 per cent. dieldrin, heptachlor and Thiodan were also tested at double the intended rate of 5 oz. per bushel.

No form of chemical control was completely effective in suppressing damage but all gave some, and usually a great, improvement, particularly on late-sown or backward crops. Most of the insecticides tested gave closely comparable results. Seed dressings containing at least 40 per cent. heptachlor, dieldrin, aldrin or γ BHC were slightly more effective than combine-drilled insecticidal treatments, with the added advantage of applying only relatively small amounts of persistent insecticides to the soil.

Slight symptoms of phytotoxicity were observed on two sites in 1958 following the use of γ BHC and dieldrin seed dressings applied at the normal rate of 2 oz. per bushel and severe symptoms on two trials in 1959 to seed over-dressed with insecticide and organo-mercury; elsewhere the seed dressings employed appeared to have no adverse effect upon plant establishment.

Dieldrin, aidrin, heptachlor and Thiodan seed dressings behaved similarly in killing a high proportion of larvae within attacked shoots; γ BHC reduced the number of larvae entering the plant, but those which did succeed in entering developed in an apparently normal manner.

On fields where drilling was delayed and the attack severe, the optimum rate of combine-drilled aldrin was probably between 1 and 2 lb. active ingredient per acre. No significant increase in yield was obtained at rates much higher than 2 lb. per acre. While fine-dust formulations gave effective results, the use of a granular fertiliser base improved the flow through the combine-drill and gave increased tillering with slightly higher yields. Heptachlor combine-drilled at 2 lb. active ingredient per acre was slightly superior to aldrin at the same rate.

No adverse effects were recorded when insecticidal seed dressings and combine-drilled aldrin were used together, and at high levels of infestation the double treatment gave increased yields, though insufficient to justify its use on fields having only moderate egg populations.

Host choice and winter-host leaving in emigrants of bird cherry–oat aphid, Rhopalosiphum padi (Linnaeus), were investigated in the laboratory. In settling choice tests, emigrants collected from the winter host, Prunus padus, preferred this plant over a summer host, oats. Emigrants which had left P. padus for up to 24 h did not express a preference as a group, and those which had left for 24–48 h preferred oats. Eighty seven percent of emigrants caged as fourth-instar nymphs on P. padus leaves abandoned the host by the second day of adult life, and apparently did not subsequently return to the leaf. In an olfactometer, P. padus leaves which had supported spring generations of R. padi were repellent to emigrants. Volatiles were entrained from uninfested and R. padi-infested P. padus using cut twigs in the laboratory as well as intact twigs on a tree in the field. Entrainment extracts from uninfested P. padus had no effect on emigrants in the olfactometer, whereas those from twigs infested with nymphal emigrants were repellent. The study indicates that in R. padi, host-alternation is driven by behavioural changes which occur in individuals as well as between morphs.

Energy dispersive X-ray spectrometry was used to make quantitative determinations of the elemental composition of plasma-ashed apterous and alate individuals of Metopolophium dirhodum (Walker) and Rhopalosiphum padi (L.). Both morphs of M. dirhodum were reared on wheat grown in potting compost as were the morphs of R. padi but the latter were reared also on oats, free from or infected with barley yellow dwarf virus (BYDV), grown in potting compost. The data were statistically analysed by various multivariate methods, which demonstrated that alatae of both species were more readily separated by their chemoprints than were apterae. There were also clear differences, again in both species, between the two morphs from wheat and the two from oats; the main discriminant elements for R. padi were Fe, Al and Mn, and for M. dirhodum they were Cl, Ca and Al. Alatae of R. padi from healthy and BYDV-infected oats were clearly differentiated from each other and from their apterae; both groups of apterae could also be separated but not as distinctly as the alatae. The discriminant elements for these separations were Fe, Zn and Mn, and possibly Al. The differences between alates, and between alates and apterae, may reflect fundamental differences in homeostatic and metabolic processes in alate and apterous morphs of R. padi.

The results presented in this paper apply to conditions in Wales. Although admittedly based on limited data, they show that of the nine species of ticks found in the Principality, only Ixodes ricinus, L. is found on sheep, cattle and horses.

It has been observed that the distribution of ticks throughout Wales is influenced by superficial soil deposits: studies in north, central and south Wales have shown, however, that the vegetation index from which ticks are recovered is variable. Analysis of soils from which ticks are recovered, gave a pH range of from 4·4 to 5·2, and the relationship between “mat” and soil acidity is discussed.

An investigation of four adjoining tracts of vegetationally different land—rush, bracken, heather-winberry and ley—showed that greater populations and a greater rate of activity were apparent in rush land. The significance of topographical location in relation to tick infestation even on land with the same vegetation index is indicated. A salt marsh adjoining an infested non-salt marsh was found to be free of ticks.

The occurrence of a unimodal activity curve is described for central and north Wales. Within a recognized bimodal activity belt irregularities of tick periodicity on cattle have been observed at some farms. This appears to be related to the nature of the sward, and, where good pasture occurs alongside “islands” of damp ground, such discrepancies are noted.

Such “islands” may harbour ticks, while the rest of the pasture is free. When, as the result of certain influences, cattle move to these “islands” they become infested. A meteorological condition is described which leads indirectly to such movement through the agency of the warble fly.

From October 1918 to February 1919 inclusive I was stationed at Basrah, Lower Mesopotamia, and during that time I was able to devote some time to the collecting of Culicidae and their larvae.

Although, among the very numerous species of Diptera described by the late Dr. Hermann Loew, the types of not a few are stated to have been obtained in Asia Minor, nothing whatever relating directly to the Diptera of the dardanelles has hitherto appeared in print. A paper by Loew on a collection of Diptera made near Varna* is, however, worth bearing in mind in connection with any future work on the Dipterous fauna of the Dardanelles. The paper in question includes records of seven species of Tabanidae, some of which are among those mentioned in the following pages.

Larvae of Pimpla instigator (F.) were found to pass through five larval instars during development. Initial studies of external morphology identified only three morphological groups: the primary larva (L1) the intermediate larvae (L2−4) and the final instar larvae (L5). Biometrical study of the maximum head width, width of buccal mask, inter-metatentorial distance and diameter of spiracles permitted morphological separation of all five larval instars. Under a 16 h photophase (at 25±1°C; 70±10% r.h.) and an 8 h scotophase (at 15±l°C; 80±10% r.h.) the 2nd, 3rd and 4th larval instars were found to last about 24 h each, and the 5th instar 9±1 days. Progressive development of the genital buds during the 5th instar and prepupal stages facilitated sexing of the larvae.

A new tribe allied to the Telsimiini and Sticholotini and a new genus are erected for Ghanius karachiensis sp. n., a Coccinellid predator of Cerococcus hibisci Green in Pakistan.

A comparison of the mosquito fauna in a forest near Zika forest, Uganda, in July-August 1971, showed that Mansonia (Coquillettidia) fuscopennata (Theo.), Culex (C.) annulioris Theo. and M. (Mansonioides) africana (Theo.) made up 84% of the catch taken at 24-h human baits in a horizontal transect, whereas M. (C.) metallica (Theo.) made up 90% of those taken at rest. Precipitin tests showed that 98% of M. metallica and most individuals of the other Coquillettidia spp. had taken avian blood, but that two out of seven individuals of M. fuscopennata had taken primate blood. In olfactometer studies M. metallica did not respond to the human hand or a chicken. It is concluded that none of the Coquillettidia spp. caught resting, except M. fuscopennata, has any preference for man.

In 1960–63, fifteen field trials were carried out on tea estates in Ceylon to find whether dieldrin at 1–5 or 3 Ib. per acre applied as a spray to the tea bushes immediately after pruning would afford control of the shot-hole borer, Xyleborus fornicatus Eichh. Koutine sampling by a method that is described was carried out for three years after spraying, and fluctuations in the numbers of live stages and galleries of the Scolytid were recorded.

In unsprayed plots, the beetle population left in the old wood of the tea bushes after pruning at first declined, but began to rise about nine months later. Sampling was then continued in the new wood that grew after pruning. In this, the numbers of galleries and live stages increased to a major peak late in the second or early in the third year and then declined; there was a smaller increase later in the third year in several of the trials. By comparison, dieldrin at 1·5 lb. per acre greatly delayed the build-up of attack and effected an average reduction in gallery numbers of 81 per cent, by the eighteenth month and 70 per cent, by the twenty-fourth month. The main peak of attack was delayed until the early part of the third year, and the maximum level averaged only about half of that on unsprayed plots; but control in the third year was less satisfactory and more variable than in the second year. Spraying with dieldrin at 3 lb. per acre did not give better control, and no difference in effectiveness was found between 1·5 lb. applied as a high-volume (90 gal. per acre) and a low-volume (8 gal.) spray.

Special sampling in two trials revealed that reinfestation of sprayed plots began at edges adjacent to infested unsprayed plots and continued progressively inwards. It is concluded that the duration of control from spraying will be influenced by the size of the area sprayed and the proximity of infested tea fields, and that on estates, where fields of 20–40 acres would be sprayed, the level of control will be at least as good as that observed in the trial plots of 5–10 acres.

The main drawback to the use of dieldrin is that it induces outbreaks of tea tortrix, Homona coffearia (Nietn.), by killing off the parasite Macrocentrus homonae Nixon. The possible use of less persistent insecticides is discussed, together with the timing of chemical control measures in relation to cultural practices.

The numbers of open galleries (entrances visible) were closely correlated with those of live stages of the beetle up to the time of peak attack and less closely afterwards, probably because the entrance holes healed up at varying rates. The proportion of immature stages (eggs, larvae and pupae) in the population fell from the first to the third year; the fall was most rapid in unsprayed plots after the second-year peak of attack. One-tenth of adult beetles counted were males, but the true proportion in the broods was estimated to be between one-third and one-fifth. The frequency distribution of gallery numbers showed that invasion of new wood starts at random and becomes increasingly over-dispersed (more uniform) as the density rises. This would be expected if there is a maximum density of galleries that is much the same in all the tea bushes. There was some evidence for a density-dependent regulation of borer numbers brought about by intra-specific competition for wood suited to gallery formation and brood-rearing. Other possible factors influencing density are discussed.

In Britain adults of the clouded drab moth, Orthosia incerta (Hfn.), appear in the spring and are especially common during April and early May. The larvae feed on various trees and shrubs from May to June or early July, and in orchards may cause damge to the flowers or developing fruitlets. There are six larval instars. These are described, and illustrations are given of the immature stages and adults.

In different parts of the world, aphid populations and their natural enemies are influenced by landscapes and climate. In the Neotropical region, few long-term studies have been conducted, maintaining a gap for comprehension of the effect of meteorological variables on aphid population patterns and their parasitoids in field conditions. This study describes the general patterns of oscillation in cereal winged aphids and their parasitoids, selecting meteorological variables and evaluating their effects on these insects. Aphids exhibit two annual peaks, one in summer–fall transition and the other in winter-spring transition. For parasitoids, the highest annual peak takes place during winter and a second peak occurs in winter–spring transition. Temperature was the principal meteorological regulator of population fluctuation in winged aphids and parasitoids during the year. The favorable temperature range is not the same for aphids and parasitoids. For aphids, temperature increase resulted in population growth, with maximum positive effect at 25°C. Temperature also positively influenced parasitoid populations, but the growth was asymptotic around 20°C. Although rainfall showed no regulatory function on aphid seasonality, it influenced the final number of insects over the year. The response of aphids and parasitoids to temperature has implications for trophic compatibility and regulation of their populations. Such functions should be taken into account in predictive models.

Many tomaspidine froghoppers are pests of crops in South America, and their current taxonomic position frequently does not reflect their true affinities. In this second revisionary contribution, certain generic features of Tiodus, Iphirhina, Tunaima and Urubaxia are described and compared, and 2 species are transferred to Maxantonia, 3 to Tunaima, 1 to Kanaima, 1 to Prosapia and 5 to Mahanarva. Huaina gen. n., Choconta gen. n. and Tiodus rufescens sp. n. are described. Monecphora fortunata Lall. is suppressed under Kanaima vittata (Wlk.), and Maxantonia scita (Wlk.) is recalled from synonymy with Monecphora quadrifasciata (Lep. & Serv.).

A method of assessing the physical condition of grain residues is described. It consists of utilising data obtained by taking the weight and volume of samples before and after sieving over a 1/10-inch mesh.

The application of this method to a survey of the insect population of wheat residues beneath the floor of a small granary in southern England is described. Information from the weight and volume data obtained enabled the samples to be classified in a manner agreeing with visual estimates. It had the advantage of objectivity.

Three vertical series of samples were taken and analysed, and the insects present counted and identified. The size, composition and distribution of the insect population is briefly discussed in relation to the condition of the residues and their depth below the surface. The fauna consisted of grain pests (Sitophilus granarius (L.), Oryzaephilus surinamensis (L.), Ptinus tectus Boield., P. fur (L.) and Hofmannophila pseudospretella (Stnt.)) and incidental species (fungus feeders and ground-dwellers) and the two groups differed in their distribution and in their apparent response to the physical conditions.

The responses of individually marked males of Glossina morsitans morsitans Westwood to decoys (9 × 3-mm rectangles of 2-mm-thick brushed nylon) baited with sex pheromone (15,19,23-trimethylheptatriacontane) were studied after their release onto an island in Lake Kariba, Zimbabwe. Some 45–60% of resighted flies were seen on decoys, the percentage being greater for flies released at an older age. For flies released on emergence, the mean age at first contact with decoys on a static screen was 6.6 days, an average of four days later than their first observed contact with a bait ox. There was great variability in the response towards decoys on successive contacts. In general, the intensity of the responses to decoys in the first minute after contact (the ‘pre-copulatory’ responses) decreased from one enounter to the next in a single 1–2-h observation session, but were restored to high levels after an interval of several hours. The intensity of responses towards decoys after this initial period (the ‘copulatory’ responses) were not affected by previous contacts. Neither previous sexual experience nor age at first contact affected the durations of response on decoys. There were no differences between the responses of wild flies and those from a laboratory colony. The results are discussed in relation to the use of decoys with chemosterilant for tsetse autosterilization. Over 60% of flies contacting decoys did so more than once, which would increase, cumulatively, the chances of their being sterilized.

Three new species and one new genus of Eulophidae are described, namely, Wichmannia pictipennis sp.n., reared from small bark beetles living in Euphorbia in the Canary Islands, Myrmokata diparoides gen.et sp.n. which parasitises ants of the genus Crematogaster in Cameroun, and Colpixys gigas sp.n. which destroyed more than 80% of the larvae of a Languriid beetle in the stems of elephant grass in Ghana. The genera Wichmannia Ruschka and Colpixys Waterston previously each included only one species.

Glossina pallidipes Aust. was captured from a moving vehicle and in Moloo traps at three-week intervals from October 1975 to December 1976 in the Kibwezi Forest, Kenya. The percentage of teneral flies captured was about twice as high in the vehicle samples as in the traps. Samples in the traps were mainly of older flies, especially parous females. The numbers of G. pallidipes collected in the traps during 20 two-day periods were correlated with those collected from the vehicle. The vehicle-catch levels were less variable than those in the traps. By both methods the highest numbers were collected in September (cold season) and the lowest in November-December (short rains). Attraction to the vehicle followed a bimodal diel pattern at all seasons, with a higher morning (09.30–10.00 h) than afternoon (17.30–18.00 h) peak, and a midday depression at 13.30–14.00 h; the afternoon peak was much reduced in parous females. At all seasons, only one distinct peak (at 15.00–17.00 h) and very low catches at night were exhibited by flies attracted to the traps.

Crematogaster rogenhoferi (Hymenoptera: Formicidae), an omnivorous ant, is one of the dominant predatory natural enemies of a soft scale pest, Parasaissetia nigra Nietner (Homoptera: Coccidae), and can effectively control P. nigra populations in rubber forests. Olfaction plays a vital role in the process of predation. However, the information about the molecular mechanism of olfaction-evoked behaviour in C. rogenhoferi is limited. In this study, we conducted antennal transcriptome analysis to identify candidate olfactory genes. We obtained 53,892 unigenes, 16,185 of which were annotated. Based on annotations, we identified 49 unigenes related to chemoreception, including four odourant-binding proteins, three chemosensory proteins, 37 odourant receptors, two odourant ionotropic receptors and three sensory neuron membrane proteins. This is the first report on the molecular basis of the chemosensory system of C. rogenhoferi. The findings provide a basis for elucidating the molecular mechanisms of the olfactory-related behaviours of C. rogenhoferi, which would facilitate a better application of C. rogenhoferi as a biological control agent.