There are certain frequently observed and rather mysterious phenomena associated with the bionomics of the better known species of Glossina; such, for example, as the local disparity between the sexes and the apparently arbitrary distribution of the fly. It is difficult, if not impossible, to explain these, or at least no explanation has yet been put forward which is wholly in agreement with all that has been recorded of the subject. It appears necessary in consequence to consider some part of the generally accepted bionomic history of these liies as being based on insufficient evidence.

In a highly interesting article in a previous number of this journal (vol. iii, p. 343) J. Dewitz discussed “The bearing of physiology on economic entomology,” and gave in this connection, amongst other things, an account of the various kinds of tropisms and their use, besides which he also pointed out the necessity for studying these for the purpose of discovering weapons for fighting noxious insects. It strikes me, however, as if the importance of chemotropism had not been emphasised in this survey as in my opinion it ought to have been, and the purpose of these modest lines is partly to draw attention to two important researches in this branch of science, recently carried out independently of each other, partly to point out that with the aid of chemotropism we shall in all probability be able to discover new weapons for the fight against noxious insects.

The following is a summary of the conclusions arrived at in the foregoing paper:—

(1) the species sinensis, barbirostris, umbrosus, albotaeniatus and asiatica have been considered valid;

(2) the species vanus, annularis, minutus, paeditaeniatus and separatus have been rejected as invalid;

(3) certain new characters of the valid species have been noticed;

(4) the descriptions of the species have been revised;

(5) the genus Patagiamyia has been rejected, as also the genus Lophoscelomyia, both having been included in the genus Myzorhynchus;

(6) it is suggested that the Myzorhynchus group forms a series sufficiently distinct from other Anophelines to make it advisable to give it a separate generic title.