THE CANADIAN ENTOMOLOGIST 107 



most thorough account of the complex development of the bee egg 

 yet published, and to those interested in bees no apology for in- 

 vestigations of this kind is needed. It is of interest to the bee 

 enthusiast, for, while possibly he may not fully appreciate all the 

 details discussed, he will assuredly want to take such facts as his 

 training permits." With all of which we most heartily agree. 

 As a class, beekeepers are the greatest of enthusiasts, but it was 

 well that Dr Phillips exercised his usual caution and used the 

 qualification "as his training permits," for we can imagine the 

 untrained bee enthusiast in a commendable endeavour trying to 

 master the terminology of the cytologist and embryologist, to 

 unravel the desciiption of mitotic phenomena and to decide for 

 himself, for there is no room for indecision in beekeeping, as to 

 the origin of the mesenteron. With a profound conviction of the 

 marvellous nature of the processes that go on during those seve.nt>- 

 six hours required for the development of the egg, a deep admira- 

 tion for the author who has so skilfully studied and described those 

 changes and pride in the possession of such a work, he will lay it 

 down and slip away to his apiary to see whether any of his colonies 

 need requeening. 



Dr. Nelson's monograph constitutes a very valuable contribu- 

 tion to our knowledge of insect embryology, a branch of our science 

 which has received all too little attention on this continent. It 

 is a useful work mainly for two reasons. First, the author has 

 investigated, with the aid of improved technique and modern 

 methods of research, a problem previously studied in considerable 

 detail by such workers as Biitschli (1870), Kowalevski (1871), and 

 Grassi (1884), upon whose results we have necessarily had to rely 

 for our knowlede of the embryology of this insect. Secondly, the 

 author has not confined himself to a description of the results of 

 his own careful work, but he has brought together in a desirable 

 form the main results of other workers on insect embryology upon 

 which subject, accordingly, the volume constitutes almost a com- 

 plete review, and on that account will be of great value to students 

 and others desiring such information. 



The author describes in sequence the embryological changes: 

 Cleavage, formation and completion of the blastoderm, the forma- 

 tion of the germ layers, and the amnion. After a general account 



