The relative size of the compound eye constitutes a good phase character in Locusta migratoria migratorioides, the ratio E/D (length of elytra to the maximum vertical diameter of eye) being over 15 in the males and about 16 in females of the gregarious phase, as against about 13 in the males and about 14·5 in the females of the solitary phase.

Through Dr. O. W. Richards, the Imperial Institute of Entomology has recently received for identification specimens of a Trichopria parasitic on two species of tsetse-flies. It appears to be new and, since it may play a part in the control of its hosts, is described below.

Studies of the food-plant associations of Heliothis armigera have elicited the information that, for all practical purposes, egg-laying may be considered as confined to the period of florescence. Evidence of coincidence of the oviposition and flowering curves is submitted for 21 species of short-flowering crops and 8 species of long-flowering crops. All told, records taken in nearly 1,000 crops have been consulted for the conclusions drawn.

As regards short-flowering species, the peaks, as well as the confines, of the oviposition and flowering curves are related closely. But oviposition on long-flowering species may decline while flowering is still in progress, or two or more waves of oviposition may be evident according to the number of moth flights spanned by the flowering period. The courses of oviposition on long-flowering species of crop in the given instances are interpreted through knowledge of the train of moth flights: although egg-laying in quantity occurs within the flowering period, peak layings frequently are not aligned with maximum flower production because the calendar times of moth flights are displaced in relation thereto.

Edwards (Bull. Ent. Res., 1930, 21, p. 290) originally described this species from the Belgian Congo. Two further adults from Ndola, N. Rhodesia, were examined by Evans (Mosquitoes of the Ethiopian Region, II, Anophelini, 1938, p. 246) who noted that these differed from the type species in having the costa without a pale sector spot and the third vein with a large dark area at the apex. The present specimens (also from Ndola) show that these differences are not constant; in one of the two females there is a small sector spot present on one wing, the other wing and both wings in the second female have no sector spot, both females have a rather small dark area at the apex of the third vein. In two of the three males a sector spot is present on both wings, while in the third specimen this spot is absent from both wings. On the whole the wings may be said to be darker than those of typical walravensi from the Congo, and these Ndola specimens may be taken as representing a darker form but not worth subspecific rank. Associated with these five adults were four larval pelts and five pupal pelts obtained from isolated specimens. We therefore take this opportunity of describing the larva and pupa.

Pyrilla perpusilla, Wlk., is one of the most destructive sugar-cane pests in the Punjab. It is widely distributed and, in addition to sugar-cane, it also feeds on wheat, barley, oats, maize, “chari” and a number of grasses.

Descriptions of the egg, nymphal and adult stages are given.

A female can lay 773 eggs in its life-time. The eggs are laid in clusters on the food-plants and are covered with whitish fluffy material. The egg stage occupies 7–12 days during April–October and 20–41 days during November–March. There are five nymphal instars. The nymphal stage occupies 24–65 days during April–September and 78–208 days during October–March.

Both adults and nymphs do damage. They prefer to feed on those varieties of sugar-cane which have broad, fleshy and succulent leaves and thick, soft stems. As a result of their feeding sucrose is reduced by as much as 34·2 per cent., while the glucose ratio may be trebled.

The pest is parasitised by the following insects:—Ooencyrtus papilionis, Ashm., Tetrastichus pyrillae, Craw., and Lestrodryinus pyrillae, Kieff. (Hymenoptera); and Pyrilloxenos compactus, Pierce (Stylopidae). The following are predacious upon it: Brumus suturalis, F., Chilomenes sexmaculatus, F., Coccinella septempunctata, L., and C. undecimpunctata, L. (Col.), and Epipyrops sp. (Lep.). The incidence and duration of the life-cycles of these parasites and predators are given.

To control the pest the following measures are suggested:—(1) Destruction of the adults by hand nets during April; (2) destruction of the eggs by crushing during April; (3) destruction of the nymphs by a new hopperdozer during November–March; (4) dusting with nicotine dust or spraying with nicotine sulphate-fish oil soap mixture.

This species is found on most of the islands of the Seychelles archipelago including the sand cays of the Amirantes group. It is said to have been introduced about sixty years ago to prey on the Coccid pest Icerya seychellarum, which is reported to have been the most serious pest of coconuts in the Colony at that time. The Icerya is the only prey of R. chermesina, and the latter has evidently kept the former in check on coconut but is unable to prevent occasional damage being done to fruit and other trees. The plants most frequently damaged by Icerya are:—Jak fruit, bread fruit, banana, avocado, citrus and forest tree seedlings, notably Eucalyptus, Albizzia and Casuarina. On certain islands where Rodolia is not present Icerya still occasionally damages coconut. Vedalia cardinalis, the famous predator of Icerya purchasi, also feeds on Icerya seychellarum in captivity, but, to date, liberations have failed to establish this species in Seychelles. Hence R. chermesina remains the most effective known predator of I. seychellarum under Seychelles conditions. No parasites are known from R. chermesina in Seychelles, but the black ant, Technomyrmex albipes, which constantly attends Icerya in large numbers, drives away the Coccinellid.

1. The removal of the thicket windbreak from around a residual forest island considerably alters its climate and intensifies the rigours of the dry season. The evaporation rate becomes much higher; appreciable increases are caused in the atmospheric diurnal temperature, but are more pronounced in the soil temperature. The island becomes slightly colder at night.

To be forewarned is to be forearmed and it is for this reason that the following information has been written concerning a gall midge which has recently been reported attacking apple blossom in Japan and another gall midge which attacks black currant flowers in Finland. Both prevent the formation of fruit. It is possible that either or both of these pests may appear in other countries.

(1) An extensive survey covering a period of 18 months was carried out in Zanzibar, Algeria, Morocco and some parts of France with a view to obtaining parasites of white grubs for furthering the control of Phytalus smithi, Arrow, in Mauritius.

(2) In Zanzibar the results of the survey showed that white grubs are of no great economic importance in clove plantations in this Island. Larvae of several species of white grubs were obtained, viz.: Entyposis impressa, Kolbe, Schizonycha spp., Anomala delagoa, Pèr., etc. ; these larvae are parasitised by the Dexiid fly, Microphthalma disjunctum, Wied. The percentage of parasitism at the time of the survey was from 0·10 to 0·53 per cent. Scoliids were not in great number ; the parasitism amounted to 0·6 per cent. Parasites of adult beetles were obtained on the following insects: Entyposis impressa, Kolbe, Schizonycha spp. and Anomala plebejus, Ol., the parasites being Pexopsis pyrrhaspis, Villen., and an Adapsilia, not yet determined. The parasitism on the above mentioned beetles varied from 1 to 9·7 per cent.

Egg Parasites.—In the Eastern Transvaal, Swaziland and Natal the eggs of Heliothis armigera are parasitized by Trichogramma luteum, Gir., and Telenomus (Phanurus) ullyetti, Nixon. No other egg parasites have been encountered.

Representative samples of eggs were collected weekly or twice-weekly over a period of seven years and over wide areas from the various cultivated crops and colonies of wild food-plants which exemplify the annual chain of breeding sites of H. armigera. The collected eggs were incubated to determine the “active” fraction derived after withdrawal of the infertile portion and of eggs exposed for less than 24 hours to parasite action. Observed parasitism was computed against the “active” eggs and is regarded as an index of the parasitism in the field. Running indices of this nature are given graphically to indicate the annual incidence of egg parasitism in percentages, which may be viewed in relation to the incidence of bollworm as evinced by oviposition data in the figures given. Sustained high levels of parasitism are associated mainly with the more abundant egg populations on winter-irrigated vegetable crops grown between July and November.

It has been found that Telenomus occurs mainly in the period August to December, and Trichogramma in the period December to March–April. The high parasitism of the winter egg populations is due, therefore, almost solely to Telenomus.

Evidence is submitted that the levels of parasitism in certain crops are commonly much higher than in others. Explanations are suggested by consideration of sites of egg deposition, accessibility of eggs, plant habit, vegetative and flowering, and, particularly, the known oviposition-flowering relationship of Heliothis moths. The latter has an important bearing on the persistence of host material and governs opportunity for the intervention of parasite progeny in increasing numbers.

Records on the status of egg parasitism have been taken in conjunction with investigations of the extent of larval mortality associated with the various types of crop. The rôle of egg parasites as agents reducing the issue of moths from winter and spring breeding areas is discussed briefly. Comparisons are given to show that the influence wielded is inappreciable even in some cases where parasitism is particularly high.

An account is given of four gall midges whose larvae damage the seed of cocksfoot, viz. Contarinia dactylidis (H. Lw.), Dasyneura dactylidis, Metcalfe, Sitodiplosis dactylidis which is described from England and Ireland in the present paper, and Stenodiplosis geniculati, Reuter. The occurrence of predacious midges of the genus Lestodiplosis is also noted.

A short section is devoted to characters by which these midges can be distinguished.

Stenodiplosis geniculati is recorded from one English and two Irish localities on cocksfoot grass for the first time, hitherto it has always been recorded from foxtail. These midges, together with some experimentally bred on cocksfoot from foxtail parents, exhibit the typical characters of this species.

A new variety, Stenodiplosis geniculati var. dactylidis, is described from cocksfoot in New Zealand.

In a discussion of the host-plant specificity of gall midges attacking grass seeds, it is suggested that the present discovery of S. geniculati on cocksfoot in England and Ireland and the occurrence in New Zealand of this new variety exhibiting distinct morphological characters are two steps in the evolution of a new species.

I am indebted to Miss F. M. L. Sheffield for taking the photographs used to illustrate Plate IV. They were taken to show the comparative lengths of the antennal segments and not the chaetotaxy. I am also indebted to Mr. P. S. Milne who took the photographs used to illustrate Plate V.