The three species of the genus Mus mentioned above follow in the wake of civilised man and may be looked upon as more or less domestic animals. Moreover, when they appear in any new locality, they seem to possess the power of eliminating the previously established native species of rats and mice, and they thus obtain for themselves a wider field and the opportunity for a rapid permanent increase in number of individuals. Of the three, Mus rattus alone habitually infests ships, but by accidental transference in vessels from port to port all three have become distributed throughout the world. Australia is especially rich in peculiar local species of rats, abundantly distinct from, but to some extent resembling, Mus rattus. This circumstance renders it not improbable that on occasion animals from Australia may have been incorrectly identified with that cosmopolitan species.

Having taken part as a volunteer in the great yellow fever epidemic of 1905 in New Orleans, I was later in the same year sent by the Colonial Office to enquire into yellow fever in British Honduras and the adjacent Central American Republics.

The family of the Trypetidæ is of great economic importance, for among its numerous genera are to be found many pests of the orchard and farm. The flies of this family are rarely brought to the notice of Europeans in West Africa, for there farming operations are entirely in the hands of the native population and the amount of damage done by these insects is perhaps insufficiently appreciated by Europeans; but from observations made in my own gardens, during a long West African experience, I believe the loss caused by their attacks must be considerable. The flies which are responsible for the damage observed belong to two genera—Ceratitis, MacLeay, and Dacus, Fabricius.

Throughout the Nyasaland Protectorate there are many areas which are infested by Glossina morsitans; and this species is also to be found in North Eastern Rhodesia, and in German and Portuguese territory bordering on Lake Nyasa. I have been frequently through all these territories during the last 22 years, and know them well.

In dealing with this extremely interesting and valuable collection of Mosquito larvæ and pupae from Lagos, which we owe to the industry of that indefatigable collector and observer, Dr. W. M. Graham, I have endeavoured to give a practical and not too technical description of each species, and I have given illustrations of all tbe principal characters, and of some points of more general interest. If technicalities are indulged in, they are explained in the preliminary text, and in the plates. It has been my object to make it impossible for the careful worker to mistake any one of these larvæ for that of another species, but persons who have experience of such work, know the difficulty of arriving at such results without a knowledge of all known forms, and that knowledge I have no pretensions to possess.

Notwithstanding the work which has been conducted during the last few years on blood-sucking flies, and particularly on those which occur in Tropical Africa, owing to their connection, whether proved or merely suspected, with the spread of various diseases of man and animals, nothing has hitherto been published on the life-history of any African species of the large family Tabanidæ, except in the case of Tabanus biguttatus, Wied.* It is hoped, therefore, that the following notes on the bionomics of two of the more common Tabanids, though incomplete, may nevertheless be of some interest.

The distribution of this Tabanid as given by Ansten † is a very wide one. In Africa it occurs from the Transvaal in the south to Egypt in the north, while outside the bounds of Africa it is found in Baluchistan, India, Ceylon, china and Japan. In the Anglo-Egyptian Sudan it occurs fairly commonly in the south, but until this year it had not been recorded from the northern provinces.

In the Bulletin of Entomological Research, Vol. I. pp. 60–61, I gave an account of the ravages of a cocoa bark-sapper (Sahlbergella theobroma, Dist.), which was found destroying cocoa trees upon plantations in some parts of the Gold Coast and Ashanti, where, by reason of its wide distribution in 1909, it promised to affect the industry seriously.

Mites or Acari belong to the class Arachnoidea, which also contains the Scorpions, the Spiders, the minute False-Scorpions, the long-legged Field Spiders and some other curious eight-legged creatures. They are at present considered as a degenerating branch of the Arachnoid trunk. Their larvse are six-legged, their nymphs eight-legged, but deprived of genital apertures.

Apart from the Ticks (Ixodoidea), mites have been generally very much neglected by collectors and systematists alike; but seeing that they comprise a considerable number of species of undoubted economic importance, it has seemed desirable to call attention to them by this brief account of some of the more striking forms. A fuller investigation of their habits and lifehistories, especially as regards tropical species, is certain to yield much information that is likely to be of both practical value and scientific interest.

Through the kindness of Mr. S. A. Neave, the types of all new species described below have been presented to the British Museum (Natural History).

To render the study of Mosquitoes practically useful to the sanitary officer, it should be made possible upon catching an adult mosquito anywhere, to say : this mosquito was bred in a water-butt, puddle, bamboo, empty tin, etc. It would thus be only necessary to find and destroy the breeding-place.

♀.—Length (four specimens) 13 to 16 mm.; width of head 4·4 to 5·5 mm.; width of front at vertex 0·5 mm. to just under 1 mm.; length of wing 10 to 13 mm.

The highlands of Abyssinia are remarkably free from blood-sucking flies, if the Culicidæ, Stomoxys, and Hippoboscidæ are excepted.

In a sub-tropical city like Cairo it is most important that, so far as possible, the main streets be protected from the direct rays of a powerful sun by numerous and healthy shade-giving trees. For this purpose, the Lebbek (Albizzia lebbek) has been very extensively employed in Cairo, where it affords a welcome shade, as well as adding very considerably to the appearance of the streets. Until the summer of 1909, these trees have, on the whole, filled their parts quite satisfactorily. They had only one serious insect enemy to contend against, in the form of a longicorn beetle—Xystrocera globosa, Oliv. Hitherto this “borer” has been considered by far the most important pest of the lebbek, since its attacks, although comparatively slow in their effects on the life of the tree, are yet sure, and when extended over a period of years have caused no little mortality amongst the shade-trees of this city. During the past year the importance of this beetle has been, so far as Cairo is concerned, somewhat eclipsed by the depredations of a comparatively new pest—a mealy bug. This insect proves to be new to science, and is described for the first time in the appendix to this paper under the name of Dactylopius pertiiciosus, sp. n.

The insect of which drawings are given here (PI. VIII, figs. 1 & 2) is one belonging to the genus Helopeltis (family Capsidæ), which contains a large number of extremely injurious species. The most important of these at present known is H. theivora, Westw., the “Tea Mosquito Blight” of India, which has rendered very large areas of tea-plantations in Northern India unproductive owing to the puncturing of the immature leaves. H. antonii, Sign., has been the cause of similar destruction to tea, cinchona and cocoa in Ceylon, but in the latter plant the puncturings are upon the pod and exactly similar to those produced, by the species now figured. Dr. Trimen referred to these in ‘Nature,” xxx. p. 634, 1884.

♂ ♀. Length, ♂ (15 specimens) 8 to 8·5 mm.*, ♀ (15 specimens) 9 to 10 mm.; width of head 2·8 to 3 mm.; width of front at vertex, ♂ 0·75 mm., ♀ 1 mm.; length of wing, ♂ 8 to 8·75 mm., ♀ 9·4 to 10 mm.

At the suggestion of Mr. S. A. Neave, I have prepared the following brief notes of my observations on the changes in the distribution of Glossina morsitans within the Lundazi District.

Ovisac of female (see fig. 2, p. 124). White, or rarely pale buff. Usually more or less reniform, rarely quite globular or more or less hemispherical; surfacewith well-marked transverse, flutings and sometimes also with faint longitudinal striæ. The waxen plates and mealy secretion of the female are often visible on the exterior, more especially so in the earlier stages of the formation of the ovisac. When quite intact it has a closely felted appearance, but on the least disturbance the material is capable of stretching out into long, viscous, elastic threads interwoven with a granular or mealy secretion, which latter disperses in the form of a little cloud of white smoke.

Length 3–5 mm.; rarely attaining a length of 7 mm.