6 THOMAS SAY FOUNDATION 



on Nemoura is so fine a monograph on the structure 

 and behavior of a very primitive winged insect that 

 it mighl well serve as a text-book for an introductory 

 course in entomology. Miss Smith did comparable 

 though less extensive work on one of Say's original 

 species, Perla immarginata; and then began a syste- 

 matic treatment of the order, of which this present 

 monograph is a continuation. We have done little 

 more with that portion of the group which she studied 

 (the Pteronarcidae) than to adopt and incorporate 

 her results. 



In the course of the years during which materials 

 have been gathered for this monograph, we have been 

 aided in various ways by so many helpfully minded 

 people that it is now impossible for us to mention 

 them all by name, though we wish to acknowledge our 

 obligation to all. We are especially indebted for the 

 loan of specimens to the following museums: The 

 Museum of Comparative Zoology of Harvard Uni- 

 versity, the U. S. National Museum, the Boston So- 

 ciety of Natural History, the Provincial Museum of 

 Quebec, the California Academy of Sciences, the 

 American Museum of Natural History; also to the 

 entomological collections of Stanford University, of 

 the Universities of Illinois, Kansas, and Michigan, 

 and of the State Agricultural Colleges of Kansas, 

 Oregon, Utah, Montana, and North Carolina. 



Specimens have been received from the following 

 individuals: C. P. Alexander, Nathan Banks, C. 

 Betten, C. S. Brimley, C. R. Crosby, P. P. Calvert, 

 R. A. Coolev, J. C. Bradley, W. J. Chamberlain, 

 Norman Criddle, A. N. Caudell, T. D. A. Cockerell, 

 P. J. Chapman, William T. Davis, George A. Dean, 

 G. S. Dodds, S. A. Forbes, C, A. Frost, C. P. Gil- 

 lette, I. M. Hawley, W. E. Hoffman, S. J. Hunter, 

 \Y. E. Howard, Mrs. W. W. Hippisley, C. W. 

 Johnson, Trevor Kineaid, A. L. Lovett, J. McDun- 

 nough, A. E. Miller, Miss G. Myers, R. Matheson, 

 R. A. Muttkowski, P. B. Powell,' S. A. Rohwer, R. 



