6 DRAGONFLIES OF NORTH AMERICA 
werefar more than mere catalogs of species with records of distribution: 
that of Kellicott for Ohio, that of Williamson for Indiana, that of 
Kennedy for the Pacific States, that of Garman for Connecticut, 
that of Mrs. Seemann for Southern California, and that of Howe 
for New England. There have been excellent monographs, also, of 
lesser groups, among which three are especially noteworthy: Garman’s 
review of the Zygoptera of Illinois, and Walker’s monographs of the 
two great northern genera Aeschna and Somatochlora. For mono- 
graphic treatment of genera the two last named are models. Our 
bibliography will give testimony to the contributions of other recent 
workers. 
There is much pioneer work still remaining to be done on the dragon- 
flies of North America. Only one sex is known for a good many species, 
and there are doubtless new species yet to be described. Partial life 
histories have been traced for only about half the species, and full life 
histories for fewer than can be counted on the fingers of one hand. 
There is boundless opportunity for further study of habits and ecology 
and distribution. There is a good service to be rendered to education 
by developing methods for using dragonflies, and especially dragonfly 
nymphs, as nature study material. 
