Rhyssa persuasoria himalayensis, subsp. n.

May be separated from Rhyssa persuasoria, L., only on colour differences, of which the most important are as follows : Mesonotum with white signature, which is anteriorly acute and posteriorly broader, with sometimes the posterior angles somewhat drawn out behind ; all coxae black and white, except in the male, in which the four anterior coxae are almost entirely white ; hind legs, particularly hind femora, mainly dark to nigrescent or deep black, except in the male, in which the hind femora are mostly white ; the white lateral markings of the 7th tergite contiguous with their white apical spots respectively, except in the male.

In the following paper is given a list of cotton pests of Papua and New Guinea, with some notes on distribution and behaviour. The list makes no pretensions to being complete, but might prove useful in the event of cotton-growing being extended in that region.

In August 1925, instructions were received to accompany Mr. G. Evans, C.I.E., then Director of Cotton Culture to the Queensland Government, on a tour of cotton areas potential and actual in Papua and the Mandated Territory of New Guinea.

We sailed from Brisbane on 13th August and returned on 30th October. Of the short time at our disposal some 40 odd days were spent at sea. In consequence, the time available for collecting entomological material was not as much as might have been desired.

Les parasites suivants ont été recueillis par Mr. J. G. Myers à Versailles, France, en juillet et août 1925, de la Cécidomyie des poires, Perrisia pyri, Bch. Le matériel obtenu comprend les 10 espèces dont les noms suivent, avec indication de leurs dates d'éclosion, mais seuls les deux Platygasterines et le Torymus peuvent être considérés comme ayant une importance dans la destruction de la Cécidomyie, les autres espèces n'ayant été obtenues qu'en trés petit nombre ou n'étant probablement pas parasites de ce petit Diptère.

1.—Encarsia formosa, Gahan, is a Chalcid wasp that parasitises the white-fly, Trialeurodes vaporariorum, Westw., a single female ovipositing in 50 or more young pupae of the host. The larvae of the parasite, on hatching from the egg, destroys the white-fly pupa, the skin of which becomes black in colour, thus distinguishing the parasitised pupa from the normal white scales and pupa of the white-fly.

2.—The parasite is parthenogenetic, males, probably impotent, only appearing when temperatures are low.

3.—The life-history of the parasite occupies at least 28 days, and adults may remain in the scales for some time before cutting their way out by a circular hole in the roof of the scale. The adult is capable of travelling over large areas in glasshouses.

4.—Low temperatures militate seriously against the increase of the parasite, which is probably a tropical insect and has possibly been imported into this country from India.

5.—Fumigation with hydrocyanic acid gas, as practised commercially for the control of white-fly, does not affect the parasites.

6.—The parasite is best distributed by detaching the black pupae of white-fly from the foliage, though 20 per cent, may be injured in this way. An almost complete emergence is obtained by cutting branches from plants and pinning them to the plants in houses where distribution is desired, but this involves risk of infecting the houses with various pests and diseases.

(1) This report is an account of the experimental work carried out by the Tsetse Investigators in Northern Nigeria during the period from January 1924 to May 1926. G. morsitans and G. tachinoides are dealt with. In the Introduction the district around Sherifuri, where the camp is situated, is described, the differences between primary and secondary tsetse foci are defined, and an account is given of the method of collecting data as a basis on which to estimate the effects of experiment. Before and during experiment flies were collected week by week from foci subject to experimental change and from others employed as controls, the following factors being noted : the sex proportion in the catch, the rate of catching, the state of nutrition, the proportion of very young flies, the blood content of the guts with classification of the kinds of blood taken, and the trypanosome infection.

(2) An experiment was carried out in which game was excluded from a good secondary focus of tsetse by means of a fence. This set up a state of starvation in morsitans and to some extent in tachinoides. There was a marked reduction in the abundance of both species, especially in morsitans. More blood than usual was taken by morsitans from birds, and both species contained a larger proportion of blood of human type than is usual. Invasion of the enclosed area by tsetse from outside vitiated the experiment and resulted in certain anomalies, viz., that the rate of trypanosome infection remained high ; the blood content was not appreciably decreased ; the proportion of very young flies increased abnormally in morsitans. It is considered that game destruction, if it could be accomplished, would lead to a disappearance of morsitans, but not of tachinoides, and for this reason no policy of game destruction is recommended, but a policy of laissez faire towards the game in Northern Nigeria, so that there may be no increase in the wild Ungulata, which results in increase and spread of fly.

(3) A successful experiment in deferred grass burning is recounted. The late sweeping fire resulted in a great mortality of morsitans and tachinoides, both flies and pupae. It hardly affected the growth of established thicket, but probably checked expansion of such and the formation of new thicket. It is considered that late grass fires, well organised, might have a good effect in Northern Nigeria, but the difficulties in the way of postponement of burning are exceedingly great in this country.

(4) The commencement of an experiment in clearing with subsequent settlement is briefly described. Except on the main road through the experimental area only fringing forest is being cut down, the general woodland being left untouched. If this policy is successful only a relatively small proportion of a fly area will need to be cleared, attention being confined to the main foci.

(5) An account is given of an unsuccessful attempt to introduce into Nigeria Syntomosphyrum glossinae, a Chalcid parasite of G. morsitans in East Africa.

Euphorus sahlbergellae, sp. n.

Head, thorax, and abdomen deep black, polished and shining ; scape, flagellum (except about 17 apical joints which are darker), palpi, tegulae, all trochanters, front femora, about apical third of mid femora, hind femora at extreme apex, the 4 anterior tibiae and tarsi, basal third of hind tibiae, light red-brown ; basal two-thirds of mid femora, apical two-thirds of hind tibiae on underside, and hind tarsi, dark red-brown ; hind femora and apical two-thirds of upper surface of hind tibiae black to dark red-black ; hind coxae, and mid coxae mostly, black ; front coxae, at least at the sides, black, apically somewhat red-brown ; claws dark ; stigma and most wing-veins brown.

It has just lately been reported to the writer that Syringopais (Nochelodes) temperatella, Led., a Microlepidopteron of the family Oecophoridae, has again in Cyprus begun to assume the rôle of a major pest. Little work seems to have been done on this insect anywhere, so that it may be worth while to give a few notes on one or two interesting points that have lately been brought to light with regard to it.

On first appointment to the island, in 1923, the writer was given to understand that Nochelodes temperatella was the greatest insect pest with which the impoverished and struggling farmer had to deal ; but that this is indeed the whole truth was not entirely borne out by enquiries during the years 1924, 1925, and early 1926, for it was found that no serious endeavour to deal with the insect on the lines previously advocated by the Agricultural Department had ever been made, despite the fact that cultural methods only had been advocated, and in addition such as could easily have been carried out with the exercise of no great energy.

Broadly, the life-history of the insect is as follows :—The adults are on the wing in the late spring or early summer, some little time before the wheat is cut. It is supposed that the eggs are laid in the soil—certainly they are to be found in the soil—and that they there persist through the hot weather, hatching some time during the winter, and the larvae immediately proceeding to attack the young wheat. The pest becomes really noticeable only towards the spring, when sometimes whole areas of wheat are virtually destroyed. Pupation takes place in the soil.

So far no species of this family of Diptera have been described or recorded from the Samoan Islands. The acquisition of a species of Tabanus by Dr. P. A. Buxton and Mr. G. H. E. Hopkins is therefore of great interest.

The Tabanidae of the Pacific Islands undoubtedly form an eastward extension of the family from Papua through Melanesia to Fiji ; various species are known from the Solomons, New Hebrides, New Caledonia, the Loyalties and Fiji, but the family is unrecorded from Tonga or islands to the eastward of Samoa. The Tabanidae thus represent a Papuo-Melanesian element in the Polynesian fauna. It might be mentioned here that two species of Tabanus, T. sidneyensis and T. nigriventris, were described by Macquart from “ Sidney Island,” which has been supposed to be Sidney Island in the Phoenix group. This locality is certainly erroneous ; most of the Diptera described as coming from there are known now to be common Australian forms and these two species are in all probability also Australian. The only other species recorded from Polynesia proper is T. insularis, Walker, described from the Sandwich Islands ; this record is also certainly wrong, since the group is not known to occur in these islands, of which the fauna has been extensively collected.