Non-cultivated areas are resting, overwintering, feeding, and/or reproducing habitats for insects, and also places from where crop areas are colonized; thus, they are essential for understanding the biological control programs in agroecosystems. We developed a simulation model for a non-cultivated area of Buenos Aires province (Argentina), and we analyzed the control of Nezara viridula achieved by the action of two parasitoids: the oophagous Trissolcus basalis and the tachinid Trichopoda giacomellii, which attack older nymphs and adults. The model is a discrete time, deterministic, phenomenological, spatially homogeneous with a 1-week time interval simulation model, based on the age-structure and/or stage-structure of N. viridula and its two parasitoids. The host–parasitoid interactions were combined with a degree-day model affecting development times of T. giacomellii pupae and T. basalis pre-imaginal stages. The simultaneous attack of both parasitoid species enables the persistence of the system at low host densities, mediated by the functional response of the parasitoids, identified as population regulation factors. However, if only one parasitoid exists (i.e., only T. basalis or only T. giacomellii) the interaction N. viridula–parasitoid persisted but at higher density of N. viridula. These results explain the successful biological control of N. viridula after the introduction of T. basalis in the 1980s, when T. giacomellii was the only parasitoid present, unable to control N. viridula. Our model shows an indirect competition when both parasitoids are present: the attack of one of them diminished the potential number of hosts available to the other parasitoid species. In the field this interaction is obscured by the hibernation period which acted as a reset mechanism affecting the density and age/stage structure of all three populations. Our model was supported by field observations, and never exhibited the extinction of any of the parasitoids from the interaction.

During the last decade, multilocus analysis has gradually become a powerful tool for the studies of population genetics and phylogeography. The double-striped cockroach, Blattella bisignata, is endemic to southeast Asia, and there is currently little genetic information available for the species. We chose it as the target species to investigate a biodiversity hotspot in southwest China. Here, we report the identification and characterization of 11 single-copy anonymous nuclear markers with an average length of 378bp. These loci, isolated from a genomic library of B. bisignata, can amplify in two additional Blattella species (B. germanica and B. lituricollis). While testing these markers in representative species of Blattellidae, Blattidae and Epilampridae, some of them can cross-amplify successfully. After sequencing 30 individuals collected from southern China per locus, we found relatively high variability (approximately 3.6 SNPs per 100bp). Finally, a small-scale study was also performed to show that these markers do indeed fulfill the expectations as phylogeographic markers.

Members of the genus Tragocephala are widespread as pests of cocoa, and other tree crops, in West and also in East Africa. Those known to be associated with cocoa in West Africa are listed and observations are given on the biology of two of the more important, T. castitnia theobromae Entw. in Ghana and T. castnia cacaoensis Entw. in Nigeria, and a method of laboratory rearing and breeding is described.

The egg is laid in an unhardened stem and the oviposition behaviour is complex; the stem is first girdled at a point where it is less than one centimetre in diameter and an oviposition slit excavated above the girdle. The ovipositor is inserted into this slit and the egg is concealed inside the stem; the adult finally closes the oviposition slit with her mandibles.

The egg hatches after 11 days and the young larva bores upwards in the dead wood above the girdle. This phase appears obligatory and is followed by one in which the larva bores down into the living stem below the girdle. The mean larval period of T. castnia theobromae in the laboratory was 143 days (range, 70–228 days).

A pupal chamber is made by severing the stem beyond about 10 cm. above the end of the gallery and filling the aperture with shreds of wood. The pupal period, in the last half of which adult coloration begins to show, is about 20 days for T. castnia theobromae and 23 days for T. castnia cacaocnsis.

Laboratory evidence suggests that there is a post-pupal resting phase in the pupal chamber followed by a free-living non-feeding period; in T. castnia cacaocnsis these lasted on average 6·5 and 4·2 days, respectively, and were followed by intensive feeding on green unhardened stems. The length of life of caged adults varied greatly but the mean was 57·0 and 55·5 days for males and females, respectively, of T. castnia theobromae and 32·0 and 28·5 days for T. castnia cacaoensis. The least preoviposition period noted for T. castnia theobromae was 20 days and previously unmated males and females of this subspecies were still fertile up to at least 76 and 162 days, respectively. Mating normally initiated the bark-ringing behaviour of females and the maximum number of eggs laid by a female of T. castnia theobromae was 146. Considering only individuals that laid 25 or more eggs, an oviposition rate (number of eggs laid per day between first and last oviposition) of 0·51 was recorded for this subspecies. Host plants alternative to cocoa are listed for T. castnia theobromae and T, castnia cacaoensis.

The oviposition activity of T. castnia theobromae was least in June, July, August, December and January, whilst for T. castnia cacaoensis very few eggs were laid in the main dry season (November to the following February).

The eggs of T. nobilis (F.), T. castnia theobromae and T. castnia cacaoensis, and of another species in the Congo Eepublic, are attacked by the Encyrtid Aprostocetus lamiicidus Kerrich, which in Nigeria appears to undergo a larval diapause in the dry season. Whilst only 5·5 per cent, of eggs were attacked in Ghana, over 50·0 per cent, were attacked in Nigeria. There was an average of 11·7 individuals per egg and the ratio of males to females was 1:2·7.

The Tachinid Billaea vanemdeni Fennah was parasitic on larvae of T. nobilis and T. castnia theobromae in Ghana, where its larval stage was in the region of 197 days and its pupal stage 23 days. Incidence of attack was highest from April to July and the two main adult emergence periods were June and September/ October.

An Ichneumonid, Nadia sp., is parasitic on either larvae or pupae of T. castnia cacaoensis in Nigeria. Scolytid species incursive in wood dying after being girdled destroy many eggs in Nigeria, where geckoes and ants are thought to be responsible for loss of larvae.

Tragocephala can be a locally important pest, especially of seedling cocoa and its numbers may increase considerably if unsuitable chemical control methods are used against other pests of cocoa.

The bark-ringing habit in Cerambycidae is discussed.

The following are a few observations made on the larvae of Auchmeromyia luteola taken in Uganda. The larvae were kept in glass-topped cardboard boxes containing earth. Several attempts were made to feed them on the less hairy parts of puppies but in no case did they make any attempt to draw blood. I then placed some on my own hand. In only one instance was this successful, the details of the feeding being described below.

Meat, crushed ticks, bananas were placed in the boxes at various times, but so far as could be gathered, they were left untouched. By dampening the earth with water every few days larvae were kept alive up to a month. They would probably have lived longer were it not that the exigencies of constant travelling caused their neglect. The small immature larvae however did not seem to grow, those which pupated having been mature, or almost so, at the time of capture. The longest period between capture and pupation was 12 days, and this larva was full of blood when taken and two days later its alimentary tract was still red with blood.

In spite of the notable economic importance of the scale-insects and in spite of their extraordinary biological interest, all of which has generated a very considerable activity in their study, it cannot be said that the systematics of the group are in anything that even approaches a satisfactory condition.

A species of Trichogrammatid reared from the eggs of Entypotrachelus meyeri Kolbe (Col., Curculionidae) is described as new and is named Oligositoides semicinctium.

The material belonging to this family brought back by the expedition includes representatives of only four species, one of which, however, is apparently new. That three out of the four species obtained should belong to the Aegophagamyia-Bouvierella group is not surprising, in view of the predominance of this group in the Malagasy Subregion.

The work of Dr. J. J. Simpson (Bull. Ent. Res. v, pp. 1–36 and Bull. Ent. Res. viii, pp. 193–214) has added largely to the knowledge of the bionomics of the larger blood-sucking insects of the Gold Coast, especially of the Northern Territories of the Colony, yet up to the present time, with the exception of the records obtained from one or two stations, singularly little is known with regard to the distribution in the Northern Territories of the smaller blood-sucking insects such as mosquitos and “sandflies.”

Specimens of the two Coreid bugs described below were submitted by the Entomological Division of this Department to the Imperial Institute of Entomology for determination and were returned shortly afterwards with the intimation that both were new to science.

Andaspis dasi Williams, which was described from India, is made a synonym of A. numerata Brimblecombe, which was described from Australia. The species is now known from several localities and host-plants in the Pacific area and is often found on tea. A short account is given of its association with the fungus Septobasidium in Papua New Guinea.

A new Anopheles species of the subgenus Cellia Theobald is described from a female caught at ultraviolet light in northern Nigeria, and named A. deemingi. A description is also given of an atypical female adult of A. pretoriensis (Theobald).

Survival of Musca vetustissima Walker from egg to adult in nutritious cattle dung from pasture irrigated during the dry south-western Australian summer was measured in the field. When drowning was prevented by placing dung on a low embankment, survival was high for only the first two months of the fly season, which included the first month of the five-month irrigation period. Substantial emergence of wild M. vetustissima adults from naturally- infested dung occurred only around that time. Survival was so low during the last four months of irrigation, even in the absence of mortality caused by drowning, that irrigated pasture areas in south-western Australia are unlikely to have significantly greater potential for breeding of M. vetustissima than non-irrigated pastures during most of the summer.

Adult female (as observed in specimens preserved in alcohol) broadly oval (fig. 1, b, c), strongly convex (fig. 1, a), circular under compression; divisions of segments indicated on the dorsum by moderately deep transverse furrows: marginal area tumescent, overlapping the ventral area (fig. 1, b). Colour (of alcoholic material) ochreous, brownish, or olivaceous, very thinly powdered with white mealy secretion.

A lateral view of the terminal segments is essential for the identification of a Culicine larva, but owing to the necessity of the larva to pierce the surface film of the water with the spiracular valves at the distal end of the respiratory siphon, it will retain a position with the dorsal surface uppermost in spite of all efforts to induce it to do otherwise. Even if placed in water so shallow that there is insufficient space between the bottom of the container and the surface of the water for the siphon to be held erect, the insect will incline its siphon but keep the rest of the abdomen dorsum uppermost, thus possibly presenting a lateral view of the siphon, and showing the pecten, but the comb and anal segments will still not be in a suitable position for a detailed study of the characters to be made

The following is a description of a mosquito found to occur in the hills surrounding Tambunan Plain, North Borneo, whilst working with the Malaria Research Department, in 1939–42. It appears to represent a new variety of the Anopheles aitkeni type, which it is proposed to name Anopheles aitkeni borneensis.

The interplay between the host plant of an insect herbivore and an insect predator (here two-spot ladybird beetles; Adalia bipunctata (L).; Coleoptera: Coccinellidae), feeding upon such a herbivore was examined in the laboratory as factors possibly determining the differential abundance and success of green and red host races of pea aphid, Acyrthosiphon pisum Harris. The experiment comprised three treatments: two host plants (bean and clover), two treatment levels (control and predation) and three colour morph levels (green alone, red alone and green and red in mixture). Green morphs had higher fitness on the general host plant, bean Vicia faba, than on the derived host, clover (Trifolium pratense), in the absence of predation. Although green morph fitness was reduced by predation when infesting bean together with reds, there was no observable net fitness loss due to predation on clover in mixed colonies with red morphs. Red morphs exhibited fitness loss alone on both bean and clover, while clover plants seemingly prevented fitness loss in the presence of predation when red morphs were mixed with green ones. According to this scenario, when colour morphs existed as a mixed colony, the net fitness of either pea aphid morph was not influenced by predation on clover. Predators had significant effects only on red morphs on broad bean either when alone or were mixed together with green morphs. Thus, only red morphs experienced the benefits of switching from the general to the derived host red clover in the presence of predation. For green morphs, there was no apparent cost of switching host plants when they faced predation. Hence, the co-existence of green-red colour polymorphism of pea aphids on single host plants appears to be maintained by the morph gaining fitness on the derived host due to a host plant– and predation–reduction effect. These findings have important implications for understanding the ecology and evolution of host switching by different colour-plant host adapted races of pea aphids.