PREFACE vii 
where they may be obtained. This list of publica- 
tions has been arranged according to the method 
now in general use among zodlogists; the author’s 
name and the date of the appearance of the contri- 
bution in question are bracketed in the text wher- 
ever it has been considered necessary, and reference 
to the list at the end of the book will reveal the 
full title and place of publication of the work, thus 
avoiding cumbersome footnotes. The figures that 
have been copied or redrawn are likewise referred 
in every case to the original source. Many of them 
have been taken from the writer’s previous publica- 
tions and a few have been made especially for this 
work. The writer has likewise drawn freely upon the 
text of his original investigations already published. 
Ann Arzor, MICHIGAN, 
April 16, 1914. 
