BY R. J. TILLYARD. 349 



by far the swiftest and strongest of our Dragonflies, and that 

 therefore neither the male nor the female relies very much upon 

 concealment, both hawking freely together over the creeks and 

 rivers. 



We conclude, then, that the ratio of numbers of the sexes in 

 the "Odonata " is a ratio of equality; the idea of the preponder- 

 ance of the males suggested by a consideration of existing collec- 

 tions, and voiced from time to time by many eminent naturalists, 

 is not borne out by rearing a large number of nymphs, and has 

 its origin in the causes suggested above. 



