INTRODUCTION 5 
somewhat as does the popular nomenclature: elaps, boa and viperinus, 
etc. (signifying serpent). One of our common skimmers is Libellula 
luctuosa, the mournful one; another is L. funerea, of evil omen, and 
another is L. saturata, gorged (let us hope with mosquitoes). One 
Sympetrum is S. rubicundulum, blood red; one is S. imbuta, imbued 
with blood; one dainty little tropical ruby-spot has an apellation 
longer than its whole delicate self, of Hetaerina cruentata, dyed with 
blood; while another bears a name that in all ages and countries has 
been both feared and hated, H. carnifex, a hangman or executioner. 
But there are others with happier names: Libellula pulchella, the little 
beauty, and L. auripennis, with wings of gold. 
Our knowledge of North American dragonflies has been long ac- 
cumulating. Many species were described by the early EKuropean 
systematists, Linnaeus, Fabricius, Rambur, Burmeister, McLachlan 
and others. Earliest in this country was the ‘‘Father of American 
Entomology” Thomas Say, who described many species. Then came 
Baron Edmond de Selys Longschamps, who spent nearly all the spare 
moments of the long and busy life of a Belgian senator studying the 
dragonflies of the world. He laid the basis of our present system. 
Co-laborer with de Selys was Dr. Hermann Hagen of Ké6nigsberg, 
Prussia. He wrote the first general review of American dragonflies. 
It was included in his Synopsis of the Neuroptera of North America 
published by the Smithsonian Institution of Washington in 1861. 
This Synopsis came into the hands of Benjamin D. Walsh, an English- 
man then residing at Rock Island, Illinois, inciting him to study and 
make known during the next two years a goodly number of local 
species. 
When Dr. Hagen came to Harvard University he began to assemble 
in the Museum of Comparative Zoology what he called a ‘biological 
collection.’”’ This included immature stages, as well as adult dragon- 
flies, and provided materials for studies in ecology and development. 
It meant that the study of dragonflies should be something more than 
merely learning the names of species. This gave a great impetus to 
the study of life histories in America. 
After the publication of Dr. Hagen’s Synopsis no other general 
work appeared until 1893. Then came P. P. Calvert’s Catalogue of the 
Odonata of the Vicinity of Philadelphia, with an Introduction to the 
Study of this Group of Insects. To this excellent Introduction all 
students of American Odonata in the present generation acknowledge 
their great indebtedness. 
That was followed by other local lists among which were five that 
