THE CANADIAN ENTOMOLOGIST. 243 



life-histories, ecology and seasonal and geographical distribution have been 

 given the attention which they merit and which is necessary for a sound 

 basis of classification, A classification which is not based on morpho- 

 Ivigical characters considered in relation to and together with biological 

 data must of necessity be incomplete. One thing is certain, that only further 

 study of the bionomics of insects will settle the disputes of the "lumpers" 

 and "splitters," to use colloquial but expressive definitions. The present 

 monograph is an admirable illustration of this fact, and were this the only 

 outstanding feature of this most thorough piece of work, the author would 

 deserve the thanks of his entomological confreres. But his complete 

 treatment of w^iat he rightly characterizes as a ''neglected group" of insects 

 renders the volume additionally welcome both to entomologists and to 

 those interested in zoogeography. 



The monograph may be roughly divided into three sections, namely, 

 taxonomic, bionomic and systematic. Perhaps the most important feature 

 of the section on the taxonomy of the group is the fact that the author 

 calls attention to the necessity of a study not only of a large series but of 

 the colour pattern. The exclusive reliance upon structural features and 

 the neglect to take into consideration the colour pattern has resulted in a 

 "lumping" of species which a study of the natural colours does not sup- 

 port. A very careful study of colour patterns has therefore been made, 

 and the six excellent coloured plates illustrating the same make this sec- 

 tion of the work invaluable to the Odonatist. 



Perhaps the most interesting, and, to the writer's mind, certainly the 

 most important part of the bionomic section, is that dealing with variation 

 and geographical segregation. If more than a brief reference were 

 attempted here this review would exceed the appointed limits. In this 

 section the author has, as it were, struck a rich metalliferous vein, and we 

 are eager to follow it ; it is too rich and promising to be left, and we hope 

 it wi.l be followed up by further investigation. It is found that there 

 occur in the females varieties in colo\ir, in the lengih of the apparently 

 functionless abdominal appendages and in the depth of the third abdo- 

 minal segment and further, that there is a distinct correlation between the 

 variations of the last two structures. These variations are dependent to a 

 large extent upon locality, and hence, possibly upon climatic conditions. 

 Here then is an unrivalled field awaiting the attention of the biometrician. 

 Important observations have been made by the author upon the life- 

 history, and his work is made increasingly valuable by the excellent 



