2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



included in the key or a separate description has been given — or 

 both. Because pupation takes pLace within the last larval skin, 

 the puparium can be identified with the keys to the larvae. 



I wdsh to extend sincere appreciation to Dr. George E. Ball of 

 the University of Alberta, Edmonton, for his excellent direction of 

 the study; to Dr. Maurice T. James of Washington State University, 

 Pullman, for his constant help and advice on many problems; to 

 Dr. Willis W. Wirth of the U.S. Department of Agriculture, Wash- 

 ington, D.C., for his advice and for reviewing the manuscript; and 

 to the University of Alberta and the National Research Council 

 of Canada for their financial assistance. 



I also wish to acknowledge with thanks material loaned from the 

 following entomologists and institutions (abbreviations that follow 

 are used throughout this text) : 



American Museum of Natural History, New York, N. Y. (P. Wygodzinsky) — AMNH 



California Academy of Sciences, San Francisco, Calif. (P. Arnaud, Jr.) — CAS 



Canada Department of Agriculture, Belleville, Ont. (H. G. James) — CDA 



Canadian National Museum, Ottawa, Ont. (G. E. Shewell) — CNC 



Clemson College, Clemson, S. C. (R. C. Fox)— CC 



Colorado State University, Fort Collins, Colo. (T. O. Thatcher)— CSU 



Cornell University, Ithaca, N.Y. (C. O. Berg and H. Dietrich)— CU 



Deutches Entomologisches Institut, Berlin, Germany (W. Hennig) — DEI 



Illinois Natural History Survey Collection, Urbana, 111, (L. K. Gloyd) — INHM 



Louisiana State University, University Park, La. (H. V. Daly) — LSU 



M. W. McFadden Collection— MWM 



North Carolina State College, Raleigh, N.C. (R. L. Rabb)— NCSC 



Ohio State University, Columbus, Ohio (J. G. Rozen) — OSU 



Purdue University, Lafayette, Ind. (L. Chandler) — PU 



Rockefeller Foundation, Mexico, D.F., Mexico (J. L. Carrillo S.)— RF 



University of California, Berkely, Calif. (P. Ashlock and R. L. Usinger) — UCB 



University of Delaware, Newark, Del. (P. P. Burbutis) — UD 



University of Kansas, Lawrence, Kans. (W. J. Hanson) — UK 



University of Maine, Orono, Maine (G. W. Simpson) — UM 



University of Massachusetts, Amherst, Mass. (M. E. Smith) — UMASS 



University of Michigan, Ann Arbor, Mich. (T. E. Moore) — UMICH 



University of Missouri, Columbia, Mo. (W. R. Enns) — UMO 



United States National Museum, Washington, D.C. (W. W. Wirth)— USNM 



Washington State Universitj^, Pullman, Wash. (M. T. James) — WSU 



Methods 



A suitable technique for removing larvae from various substrates 

 has been developed (McFadden, 1961). Specimens thus obtained 

 for this study were divided into two groups: one to be reared, the 

 other to be preserved. 



Larvae were killed and preserved in 70 percent alcohol without 

 additional treatment. In the case of large specimens, the alcohol 

 was changed after a month's lapse. 



