INTRODUCTION. 



It is pleasant to find that the beginning of our 

 knowledge of North American stoneflies was made by 

 the "Father of American Entomology," Thomas Say. 

 In 1823 he described four species in Godmans 

 Western Quarterly Reporter^ and described them so 

 well that, although the types were long since lost, we 

 have been able to recognize them all. The scattered 

 descriptions that followed during the next four dec- 

 ades were mostly written by European entomologists 

 — by Newman and Newport and Walker in England, 

 by Pictet and Rambur in France, and by Burmeister 

 in Germany. The first comprehensive review of the 

 American fauna was that of Hagen, included in his 

 Synopsis of the Neuroptera of North America 

 (1861). Hagen recognized 61 nominal species in 

 North America, disposed in seven genera, 40 of the 

 species being retained in the original genus Perla. 

 This work was prepared in Koenigsberg, at the spe- 

 cial request of the Smithsonian Institution, from ma- 

 terials supplied by that institution and by collabo- 

 rators. Its publication incited Benjamin D. Walsh, 

 who then lived in Rock Island, 111., to collect and 

 study the Neuropteroids of his own vicinity. The 

 following year (1862) he published a list of the 

 species in his own collection with descriptions of a 

 number of new species. He collected so assiduously 

 that the vicinity of Rock Island, 111., has remained 

 until recently one of the best worked fields in America 

 for the Neuropteroid groups. Since Walsh's time, 

 the one persistent student of the group in America 

 has been Mr. Nathan Banks. In a long series of pa- 

 pers he has described many new forms, and he has 

 twice catalogued the American species (1892 and 

 1907). 



More recently there have been noteworthy contri- 

 butions to the knowledge of the group in America 

 by Dr. Lucy Wright Smith (now Mrs. Wilbert A. 

 Clemens) and by Mr. C. F. Wu. Mr. Wu's work 



2 V-^V^ 



