ACKNOWLEDGMENTS 



In prejoaring this list I am under great obligations to a 

 number of specialists for their generous assistance in deter- 

 mining material. To Dr. Frank E. Lutz, Curator of Insects 

 at the American Museum of Natural History, New York, 

 and my other associates there, Mr. A. J. Mutchler, retired; 

 Dr. C.'h. Curran, Dr. W. J. Gertsch, Mr. Herbert F. Schwarz, 

 and Mr. F. E, AVatson, I am much indebted. 



My thanks are also due Dr. C. F. W. Muesebeck of the 

 Bureau of Entomology and Plant Quarantine in Washington, 

 and various members of the staff, particularly Drs. M. W. 

 Blackman, E. E. Blackwelder, E. A. Chapin, W. S. Fisher, 

 P. W. Mason, Grace Sandhouse, and Messrs. H. S. Barber, 

 H. G. Barber, L. L. Buchanan, R. A. Cushman, C. T. Grant, 

 C. T. Greene, A. P. Gurnee, A. B. Gahan, D. G. Hall, Harold 

 Morrison, S. A. Rohwer, Alan Stone. 



Also to Dr. Richard P. Dow of the Xew England Society 

 of Natural History, who has answered many questions and 

 furnished me with records. 



Among the many others who have shown me their friend- 

 ship and interest are : Dr. Cornelius Betten, Cornell Univer- 

 sity ; Dr. S. W. Bromley, Bartlett Tree Research Laboratories ; 

 Dr. Charles H. Blake, Massachusetts Institute of Technology ; 

 Mr. K. F. Chamberlain, New York State Museum; Dr. P. J. 

 Darlington, Jr., Harvard University ; Dr. H. 0. Deay, Purdue 

 University; Dr. Henry Dietrich, Cornell University; Dr. 

 George P. Englehardt, Brooklyn Museum; Dr. E. P. Felt, 

 Bartlett Tree Research Laboratories; Dr. W. T. M. Forbes, 

 Cornell University; Mr. John F. Hanson, Massachusetts State 

 Agriculture College; Prof. H. B. Hungerford, University of 

 Kansas ; Dr. H. H. Knight, Iowa State College ; Mr. c' W. 

 Leng of the Staten Island Academv of Arts and Sciences ; 



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