During the study of the Nearctic Tachinidae it became obvious that, in order to secure an adequate idea of the relationships of the various genera, it would be advisable to study representatives of the family from all parts of the world, and requests for African material met with hearty response from several sources. The extensive collection made by the American Museum of Natural History Congo Expedition has already been dealt with, and the report will appear elsewhere. Mr. H. K. Munro, of Pretoria, South Africa, has forwarded his entire collection with the request that it be worked over, since very few of the species were determined. Dr. Guy A. K.Marshall, Director of the Imperial Bureau of Entomology, has also been kind enough to forward a large amount of material, and a great deal more has been promised from other sources. It was originally intended to prepare a synopsis of the South African Tachinidae preparatory to a more detailed study. However, the large number of species and genera represented in the thousands of specimens at hand makes such an undertaking so extensive that it is deemed advisable to report upon certain genera or larger groups in order that most of the material may be returned to the owners, retaining such specimens as may be necessary for further study.

Since the appearance of the first paper in this proposed series our attention has been called by Mr. E. E. Green to the desirability of developing a terminology for the various structures of the Diaspid scales which shall be more satisfactory than that at present in general use. We are entirely in accord with his view that many of the terms at present employed are not suitable and that they need to be replaced by others of more precise application.

We have decided, however, not to make any attempt at the development of such a terminology at the present time, the controlling reason for this decision being found in the belief that the morphology of the Diaspid scales—not to speak of the other groups—is still too insufficiently understood to permit the formulation of a terminology which shall be at all enduring. It is our belief that any system now devised is too likely to require extensive later modification. This is certainly the case with one recent attempt thus to devise such a system, an attempt that fails of its purpose because of lack of knowledge. From this point of view it seems best to leave the question of such a terminology until such time as at least a large proportion of the Diaspid types have been examined in greater detail.

For the present we shall content ourselves with the use of common and, in general, well understood terms or with simple descriptive phrases. An exception will be made in the case of certain terms which it seems well should be eliminated as soon as possible. One such term is the expression “ pygidial lobes ” for the usually paired structures of the pygidial margin. For these Mr. Green suggests that the term “ trulla,” which has already been employed by some authors, is better. Another substitution suggested by Mr. Green is that of “ perivulvar ” to designate the cluster of pores about the genital opening, and this we shall utilise.

It is widely known that the biological method for the control of insect pests is receiving considerable attention from Economic Entomologists at the present day. One of the insects against which this method is being tried is the common earwig (Forficula auricularia), which is a very serious pest of orchards, etc., in such countries as New Zealand where it it has been accidentally introduced from Europe.

Through co-operation between the Imperial Bureau of Entomology, Rothamsted Experimental Station, and the Cawthron Institute, Nelson, attempts have been made to control the earwig in New Zealand by the introduction of two Tachinid flies that are parasitic on it, Digonochaeta setipennis, Fln., and Rhacodineura antiqua, Meig. These flies are obligatory parasites, being entirely dependent on this particular host for the completion of their life-cycle, and they are lethal in effect. The larvae having emerged from their dead or moribund host, soon pupate, and it is in the pupal stadium that these insects can most conveniently be transmitted in cold storage. Mr. A. M. Altson, of the Imperial Bureau of Entomology, was in charge of this work in England in 1924 and 1925, but, unfortunately, owing to ill-health he was obliged to give it up. In the autumn of 1926, at the request of Dr. Tillyard, it was decided to forward a further batch of parasitic puparia to New Zealand. For this purpose large quantities of earwigs had to be captured in the field, and transferred to cages in the laboratory, in order that the parasites which emerged from the earwigs could be collected.

The question to which we have tried to find an answer is why malaria is almost absent in the southern region (II) within our field of observation, whereas it is endemic in the northern (I). We found Anopheles slightly less frequent in the former, but the difference is irrelevant, and the density of the Anopheline population in Region II is considerable, compared with almost all the European malarious countries we visited and where A. maculipennis is the local vector.

If this difference in the incidence of malaria is at all caused by a difference of the Anopheline faunas of the two regions (which need not be the case), then the biological distinctions are the only important ones. Morphological differences cannot interest us unless they are correlated with the former. Still we began by studying the latter, because they are easier to observe and to measure.

The larvae of certain flies belonging to the family Syrphidae have long been recognised as plant pests. Merodon equestris, Fab., was recorded in Great Britain as far back as 1869, having probably been imported in narcissus bulbs from Holland (Verrall). This fly is now universally known as the “ Large Narcissus Fly,” the larvae causing serious losses in nearly every locality where the narcissus is grown commercially. More recently flies of the genus Eumerus have been associated with a type of injury very similar to that caused by the larger fly, and the larvae have been recorded on a variety of host-plants in Europe and America. Chief among these hosts may be included narcissus, onion, hyacinth, parsnip, iris, and potato. The flies are commonly referred to as “ Lesser Bulb Flies ” or alternatively in some parts of North America, where they were first recorded as European introductions in 1904, as “ Lunate Onion Flies.”

The activities of the Australian Ladybird beetle, Cryptolaemus montrouzieri, Muls., are too well known to need recapitulation. It is sufficient to say that it has been introduced into many countries with a greater or lesser degree of success, generally for the control of “ mealy-bugs.”

The introduction of this beneficial insect into Egypt may present certain features of interest to other workers in spite of the fact that there is a great deal yet to be done. Series of experiments have been designed to elucidate certain points, but owing to the departure of the writer from Egypt these have been left to others to carry out. A detailed account of this work had been planned for a later date, but in the circumstances it may be as well to place on record what has been done up to the present time.

This summer I received for identification from the Entomological Department of the Experimental Station at Poltava one vial with 12 specimens (2 ♂♂, 10 ♀♀) of a new species of Scelio bred from eggs of Locusta migratoria ph. danica, collected by F. Lukjanovich, 12.viii.1925, at Priluky, Poltava province ; and later on Mr. B. P. Uvarov sent me two females of another species from Turkestan. All the representatives of the cosmopolitan genus Scelio, Latr., so far as we know, are egg-parasites of Acrididae. Some species have been bred from L. danica in Australia, but in Europe this is the first species of which the host has been recorded. Dr. J. J. Kieffer, in a posthumous monograph of the Scelionidae (Das Tierreich, Lief. 48, 1926), among other generic characters mentioned the four-jointed maxillary palpi. He further distinguished the Australian genus Neoscelio, Dodd, from Scelio by its having three-jointed maxillary palpi, besides the long metathoracic spine. Unfortunately Kieffer did not mention to which species of the genus Scelio his observation referred. I have dissected a few specimens of three species, S. vulgaris, Kieff., S. uvarovi, sp. n., and S. nikolskyi, sp. n., and can state that in both sexes of all these species the maxillary palpi are only three-jointed. The generic definition of the genus Scelio must therefore be corrected in this sense.

The observations herein recorded were carried out on a portion of the foreshore and of the low-lying front-lands in the vicinity of Georgetown, British Guiana, during the months of January, 1925, and July and August, 1926. The results obtained appear to be of sufficient interest to warrant their being placed on record as throwing further light on the breeding-habits of two important mosquitos of this Colony, namely, Anopheles tarsimaculatus, Goeldi, and Aëdes taeniorhynchus, Wied.

The principal area in which the investigations were carried out is situated to the north of Kitty Village outside of the Sea Wall and is bounded on the south by that wall, on the west by the Kitty Groyne, and on the east by another groyne (Case Groyne) erected a few years ago as part of the sea-defences. The area measures roughly from east to west about 700 yards and from north to south about 200 yards at its greatest width, and about 60 yards at its narrowest part, these being situated at the western and eastern boundaries respectively. The accompanying sketch-map gives a general plan of the area. The places from which mosquito larvae were collected are indicated on the plan, Anopheles by black spots, Aëdes by concentric rings.

Our present day lack of knowledge of the physical factors involved in the selection of breeding-places by certain types of mosquitos is to be deplored. Just why certain species choose particular types of water for their oviposition is a matter about which there is much conjecture, but it is hoped that in the near future some light may be thrown upon this subject by taking into consideration various aspects of the question hitherto uninvestigated.

Apanteles thompsoni, sp. n.

♀. Black, shining ; palpi pale ; antennae beneath fusco-testaceous ; clypeus and mandibles rufo-testaceous ; belly at base testaceous ; sides of abdominal segments 1 and 2 fusco-testaceous ; legs testaceous, with hind coxae black or blackish, hind femora and tibiae slightly infuscated at tips, and hind tarsi more or less infuscated. Wings subhyaline, stigma pale fuscous, nervures paler but usually visible to the extreme margin of the wing.

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.

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) 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.