296 THE CANADIAN ENTOMOLOGIST. 



larva at each birth, and this immediately crawls away and pupates, having 

 been nourished by special glands associated with the female reproductive 

 organs. The deadly nature of these diseases is now well known, and, as 

 the author asserts in the opening paragraph, these insects are of vital 

 importance to the prosperity and future development of tropical Africa. 



Eight years ago the author published his "Monograph of the Tse-tse 

 Flies." At that time the relation of Glossinapalpalis to Sleeping Sickness 

 had not been determined, and little was known with regard to the habits 

 of that species. Seven species of Tse-tse flies were described and illus- 

 trated. That volume is now out of print, and the present volume is an 

 attempt to bring the subject up to date. Fifteen species are described, 

 including two described for the first time. The author has made excellent 

 use of the valuable material, probably unique in its extent, which he has 

 at his disposal in the collections of the British Museum, and the present 

 account of the group will be of very great value to workers, especially to 

 those engaged in the field. The brevity of the accounts of the bionomics 

 of the species, with the exception of G. morsita?is, indicates how much 

 there is to be learnt, in what is, from the point of view of prophylactic 

 measures, the most important section of the subject. 



We note with regret that the author does not regard G. submorsitans 

 Newst. as specifically distinct from G. viorsitajis Westw., but considers it 

 as a form of G. tnorsitatis. While agreeing with the author, that the wide 

 distribution of G. moi'sitans might account t'or the variability in coloura- 

 tion, we do not think that he can ignore, as he appears to do, the 

 differences in the male genitalia. Newstead's species was created after the 

 examination of 93 examples, and the illustrations in his account of the 

 male genitalia of Tse-tse flies clearly indicate that the male genitala t;f 

 G. submorsitans Newst. are morphologically distinct from those of G. 

 morsitans Westw. in the character of the superior claspers. Newstead's 

 excellent paper is further evidence of the fact that in so highly organized a 

 group as the Muscidse, and, one might say, in the Diptera generally, we 

 shall have to take into consideration such important specific characters as 

 are indicated by the male genitalia. This fact is also shown in the study 

 of the Tachinidse. Specific distinctions cannot always be based on external 

 form, but are often dependent on other morphological characters, which 

 the systematist must necessarily take into consideration, and of these the 

 genitalia are important, not only in Diptera, but also in Lepidoptera and 

 Coleoptera. C. Gordon Hewitt. 



Mailed August, 2nd, 191 1. 



