442 NEW YORK STATE MUSEUM 



Part 7 

 SIALIDIDAE OF NORTH AND SOUTH AMERICA 



BY K. C. DAVIS 

 Tlie study leading to the preparation of this paper was made chiefly while 

 the wi-iter was a graduate student at Cornell University, 1898-1900. The 

 writer is under great obligation to Prof. J. H. Oomstocli and Mr A. D. Mac- 

 Gillivray, of Cornell, for much aid and encouragement; to Mr Samuel Hen- 

 shaw, of the Museum of Comparative Zoology, for use of the rich collec- 

 tions made by Dr Hagen and others; to Mr William H. Ashmead for the- 

 examination and loan of valuable specimens from the United States 

 National Museum; to Dr Henry Skinner for kindness shown while examin- 

 ing specimens in the Philadelphia Academy of Natural Sciences; and to a 

 number of coiTespondents and others who have given information in re- 

 gard to disti'ibution, or lent specimens for examination, or aided in other 

 ways. 



The family S i a 1 i d i d a e is of peculiar interest both on 

 account of the large size and the striking appearance of most 

 of its members and because it includes some of the most general- 

 ized members of the order Neuroptera. 



As is often the case with more primitive groups, the family 

 is a small one, including only four living genera; but it has a 

 world-wide distribution. Fortunately for our purposes, all of 

 the genera are found in our country, and representatives arfr 

 common in many sections. The four genera are represented in 

 the two Americas by only 32 species. 



Family sialidid^^^e 



The members of this familj^ differ from all other Neuroptera 

 in having the hind wings broad at the base, the anal area being 

 folded like a fan when the insect is at rest. They differ from 

 their nearest allies, the Raphididae, in the form of the pro- 

 thorax, which is quadrangular, while in the Raphididae it is 

 generally elongated. They also differ from moat other Neurop- 

 tera in being aquatic in their larval state. 



Though the family contains only four living genera, these 

 represent two quite distinct lines of development. So well 

 marked are these that they may be considered as representing 

 two subfamilies, which may be designated as the Sialidinae and 



