During investigations on the economic position of Collembola a significant attack on mangolds by one species of this group occurred at Rothamsted in the classical mangold field known as Barn Field. The particular species involved was Bourletiella hortensis, Fitch (pruinosus, Tullb.). Although the economic position of Collembola has not, as yet, been fully established, this member of the order can claim priority in the list of previously reported economic species. The first British record of injury probably by this species is that of Miss Ormerod in 1894, when she reported leaf damage to turnips in Scotland. Since then British records include as host-plants sweet peas, beans, radishes, lettuce, mangolds and soy beans. Reports from America confirm the economic position of this species, and in Canada Macnamara states “ the list of plants it is known to injure reads like an index to a seedsman's catalogue : beans, beet, cabbage, cantaloupes, carrots, clover, corn, cucumber, kale, lettuce, mangolds, onions, peas, potatoes, radishes, rye, spinach, squash, tobacco, tomatoes, turnips, violets, watermelons, wheat, wild cucumber.”

Insects inducing galls. Adult female apparently without limbs or antennae. Mouth-parts obscure. Spiracles large and conspicuous ; two pairs, occupying a position close to the posterior extremity. Anal orifice minute, setiferous. Genital orifice sharply defined. Spiracles, anal and genital orifices all included in a densely chitinous area. This dense deposition of chitin renders the interpretation of the characters difficult and prevents any accurate definition of the genus.

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.

In 1925 a brief generalised account was given of the biology of Sacadodes pyralis, Dyar, a Noctuiid moth that appeared likely to prove to be a serious pest of cotton, should the cultivation of this crop be taken up on a large scale in Trinidad. Previously little attention appears to have been paid to the potential danger, which the writer considers to be very real.

Sacadodes is not only very closely allied to Diparopsis castanea, Hampson, the Sudan bollworm, but it is also remarkably similar to that insect both in the general facies of all stages (Plates xxi and xxii) and in its bionomics.

In a series of notes and papers published in the last few years, the writer has attempted to apply simple mathematical methods to the study of the numerical increase of entomophagous parasites at the expense of their hosts. This work was undertaken mainly in the hope of bringing to light the general laws underlying parasitic interrelations, considered simply in their quantitative aspect. But since the publication of these papers the writer has frequently been questioned by entomologists as to the utility of the mathematical method in parasitological operations of the practical order.

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 name Platyedra scutigera is proposed for a cotton insect of Queensland, previously reported as P. gossypiella. Its larval and pupal stages are described and notes on its bionomics and distribution are given.

There are at least four distinct species of Platyedra in Australia, P. gossypiella in West Australia and the Northern Territory, the other three in Queensland, one of which is the cotton pest, P. scutigera, the remaining two feeding on native Malvaceae.

Thaumetopoea wilkinsoni, Tams, is known only in Cyprus, where it abounds, attacking all species of pine, but chiefly Pinus halepensis, Mill.

In the plains the adults emerge from the end of August to the beginning of October. The eggs are laid, shortly after emergence, in cylindrical masses round pine needles, the masses averaging 150 eggs. Only one mass is laid by each female. The incubation period is about 45 days.

The five larval instars are described, as well as the differences in the habits and nests in the various instars. The length of the larval life varies from 116 to 173 days. Only in the fourth do larvae remain in the same nest throughout the instar, as they frequently migrate, moving in single file to new feeding grounds, and there construct a new nest. Six such migrations have been observed for one colony during its three earlier instars.

Pupation, which commences in the plains about the middle of March, takes place in the ground in silken cocoons at a depth of ¼ to 3 inches, the pupal life lasting all through the hot weather.

Altitude considerably influences the life-history—the greater the altitude the earlier the emergence of the adult and the later the pupation of the fully-grown larvae, with consequent alterations in the length of the larval periods.

Of the checks, two species of Chalcid egg-parasites have been shown to occasion a parasitism of over 17 per cent., and three species of Tachinid larval parasites sometimes to occasion a parasitism of at least 30 per cent. There is also an Ichneumonid larval parasite. This latter aestivates in the pupa of its host ; the Tachinids leave their larval hosts and pupate in the nest of the processionary.

Re-afforestation in Cyprus, both natural and artificial, being an urgent necessity, this processionary is of great economic importance, as stands of young trees suffer very heavily from its attacks, one colony of larvae being sufficient to strip and, if the late rains fail, to kill a small tree. The writer considers, however, that control is possible by encouraging the parasites and predators, methods for which are outlined.

Numerous experiments have been performed to study the specific effect of hydrogen ion concentration, CO2 and oxygen content of water on may-fly larvae, which warrant the following conclusions :—

1. While hydrogen ion concentration is a factor of great significance, the carbon dioxide pressure is of greater importance and should afford a very reliable index of the suitability of water as a habitat for true aquatic insects.

2. May-fly larvae, and presumably other insects as well, can stand a very low concentration of oxygen, below 1·0 cc. per litre. In view of the fact that in nature oxygen content seldom goes down to such a low figure, insects should not, as a rule, die of lack of oxygen.

During a visit to the Canary Islands in the early autumn of 1924, the chief purpose of which was an inspection of the banana plantations for insect and allied pests, four enemies were found, each of which was the cause of some loss. Two of these had relatively small importance, viz. a red spider (Tetranychus) and a thrips. The red spider was known locally as the “ red bug,” the popular name being “ aranillos ” (the little spiders) ; the mites were found on the fruits, which showed the paleness and discolouration that characterise plant tissue wounded by the red spider mouth-parts. The thrips, known locally as “ black bug,” also caused a paleness and discolouration of the attacked fruit. Both of these enemies were known to the Spanish workers as “ bicho blanco ” (the animal which causes a whiteness). The other two enemies were much more serious, one of them a moth, the banana miner, Hieroxestis subcervinella, Walk., the subject of another paper ; the second a scale-insect, Pseudococcus comstocki, the subject of this paper.

An investigation of the breeding habits of the yellow fever mosquito, Aëdes aegypti, Linn., in West Africa was begun in December 1925. This was undertaken for the purpose of ascertaining if the selection of breeding-places of this mosquito in Africa differs from that in the Western Hemisphere, and, if so, to learn if this difference is sufficient to be of material importance in yellow fever control work.

Since it was believed that breeding in tree-holes constituted a problem worthy of investigation, it was decided to make a survey of the rot-holes and fork-hollows in trees in the vicinity of Lagos, in the Southern Province of Nigeria. This survey was begun on 8th December 1925, shortly after the rainy season had passed and the dry season had set in. However, after inspecting a number of trees, the fact became evident that this was not a propitious time of the year for finding larvae in such places, since practically all of the holes were without water, and their contents, consisting of leaves and débris, were dry.

This early drying of the material in the holes drew my attention to the probability of mosquito eggs remaining in the holes, surviving the drought of the dry season and producing larvae with the beginning of the rains. In furtherance of this question, an examination of the dry holes was then began, and material collected from all those that were suitable. The term “ suitable ” in this sense signifies that the hole was in a living tree—of a formation to contain water, for a short time at least—that the aperture was of sufficient size to allow the débris to be removed and the inside of the hole scraped, and that the contents were dry. The distance of the trees from habitations, their location in open areas or thick bush, the height of the holes from the ground, the exposure of the holes to the sun, or the amount of débris contained caused no discrimination to be made.

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.

The following lines may be regarded as a first additional note to a former paper of the author's (Zion. Organ. Agr. Expt. Sta., Bull. 1, July 1924). It contains 14 species not recorded in the first list, two of which are new to science. The numeration follows that of the former paper. I wish to tender my acknowledgements to Mr. W. J. Hall, Cairo, for determining some species of Diaspinae and to Mr. H. Aron for preparing the illustrations.

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.

Very small, shining black, evenly, but rather sparsely covered with very regular, equally long, pale, short, depressed hairs.

Head very strongly deflexed, including the eyes more than three times as broad as long, seen from above, but actually only a little more than one and a third times as broad as long seen in full face ; seen from the side (fig. 2, a) shorter than height at base ; frons and vertex moderately convexly arched, the vertex between the eyes about twice as wide as the diameter of one of the eyes (which are feebly prominent) ; basal margin of vertex between the eyes distinctly carinate, and slightly overlapping the anterior margin of pronotum ; clypeus flat, not at all prominent, and obscurely delimited from the frons ; rostrum extending to the hind coxae, the basal joint incrassate and reaching the base of the front coxae ; antennae moderately short, inserted close to the front margin of the eyes at about two-thirds of the distance from the base of the eye to its anterior apex, first joint slightly incrassate, cylindrical, extending to the apex of the clypeus, second joint incrassate more or less fusiform, the apex much thicker than the base, about three and a half times as long as the first joint, the third and fourth sub-equal, slightly thinner than, and about twice as long as, the first joint.

The genus A phrastobracon was erected by Ashmead in 1895 to include an interesting new Braconid that was bred out from the lac insect, Tachardia albizziae, Gr., by Mr. E. E. Green, in Ceylon, and the species was named A. flavipennis. Since then we have no further records of this insect from Ceylon or elsewhere. Even Mr. Green does not refer to it in connection with the same lac insect in his recent last volume on the Coccidae of Ceylon, though he has made mention of another Braconid, Bracon greeni, Ashm., bred by him from the same host and described by Ashmead as the same time as A. flavipennis. However, this insect was noted by the writer of this paper some years ago in South India, and latterly during the course of his studies on the local Coccidae specimens of this species were reared from two or three common scale-insects. It was at first thought to be a parasite on the scales and was identified by a well-known authority as a species of Megalommum, Sz.; a record to this effect may be found in the author's “ List of Parasitic Hymenoptera of Economic Importance from South India ” published in 1921. Further studies and observations made on the bionomics of this insect in recent years revealed its true habit as a parasite, not on the scale, but on a Lepidopterous caterpillar feeding on the scale, and its correct identification was obtained after consulting two or three specialists. A brief reference to the insect, explaining its habits, is made in the author's recently published memoir on the nim mealy scale, Pulvinaria maxima, Gr.

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.

The following notes are the result of correspondence between Major E. E. Austen, of the British Museum, and myself concerning certain specimens of the family Tabanidae that were sent to him some time ago for critical notes, which are quoted below. It is a pleasure to thank him for having on several occasions given me the benefit of his extensive knowledge of the Diptera.

During the carrying out of field work in connection with the investigation of plague in the Union of South Africa, certain fleas which appeared to be new were taken in the nests of water rats and on a golden rock mouse in the Karroo.

Whilst resembling Chiastopsylla, Rosthsch., morphologically, the fleas from the Karroo rats differ from that genus in the absence of tooth-like spines at the genal margin of the head, and the flea taken on the rock mouse differs in possessing no pronotal comb, in addition to the absence of spines at the genal margin of the head. It was thought that these differences would require the erection of new genera for the reception of these fleas ; two specimens, however, of one of the species showed an incomplete set of genal spines, and Dr. Jordan, who kindly examined the material, considers that all the fleas described below belong to the genus Chiastopsylla. Apparently, if one may judge from the presence of genal spines in the two specimens found, certain species of this genus have been recently evolved.