144 THE CANADIAN ENTOMOLOGIST 



terrestrial type. The remarkable forms constituting the suborder 

 Anisozygoptera of Handlirsch are considered to be true Zygoptera 

 of an early unreduced type, and are placed as subfamilies of Cal- 

 opterygidse and Lestidae. 



Some errors and minor defects are, of course, present in this, 

 as in all books treating of so wide and varied a field, but as most 

 of these have already been pointed out by other reviewers, we shall 

 merely call attention to the following: 



In the historical sketch in the introduction there is no mention 

 of any American author. Some reference, at least, should have 

 been made to the pioneer work of Hagen and the monumental labours 

 of Dr. Calvert, than whom no one has done more to place our 

 knowledge of the order on a sound and substantial basis. No 

 mention of Bartenef's work on the Palsearctic fauna occurs in 

 any part of the bcok. 



On page 19 the cervical sclerites and gula are stated definitely 

 to represent the skeleton of the last head-segment. This is by 

 no means an established fact, as they have also been interpreted 

 as belonging to the intersegmental membrane between the head 

 and prothorax, being serially homologous with sclerites which are 

 sometimes found in the two succeeding intersegmental areas. 



The length of embryonic life is much more variable than is 

 indicated (p. 242). Dr. Calvert has pointed out that in Pennsyl- 

 vania the eggs of Sympetrum vicinum, deposited in the autumn, 

 do not hatch until the following spring. This is also true in On- 

 tario of Boyeria vinosa and almost certainly also in the case of the 

 various species of Mshna. 



In compiling the census of the Odonata of the world (p. 299) 

 the Selysian monographs by Martin should not have been used 

 for the nearctic region in preference to Muttkowski's catalogue, 

 as they are incomplete and deficient in their treatment of the 

 North American fauna. 



We do not wish, however, to detract from the impression we 

 have tried to give of the truly admirable qualities of Mr. Tillyard's 

 book, for lack of space necessitates the omission of much that 

 might be added in its praise. It is a book that is indispensable 

 to every biological and entomological library. 



Mailed April 13th, 1918. 



