4 A VENATIONAL STUDY OF THE ZYGOPTERA 



and valuable criticism have made possible what has been accom- 

 plished. He has been very generous in the time and abundant 

 material which he has given me. Mr. C. H. Kennedy, also of Cor- 

 nell University, who has been working on the same phylogenetic 

 problem from another method of approach, has never hestitated in 

 giving me suggestions arrived at from his study, has made several 

 drawings for me and brought material from museums which I was 

 not able to visit. Dr. P. P. Calvert and Dr. Henry Skinner of 

 Philadelphia very generously loaned specimens and permitted the 

 use of the extensive collections at the Academy of Natural Sciences 

 of Philadelphia. Alir. Carl Ilg of Philadelphia kindly copied 

 several descriptions which were not available at Cornell. Mr. 



E. B. Williamson of Bluffton, Indiana, loaned valuable material; 

 Dr. Samuel Henshaw of Cambridge sent material for study and 

 permitted Mr. E. Avery Richmond of Cornell to photograph 

 several specimens at the Museum of Comparative Zoology. Mr. 

 Rolla P. Currie and Miss Currie were very kind and helpful in 

 allowing me the use of the collections at the National Museum. 

 Dr. W. J. Holland and Mr. Hugo Kahl of the Carnegie Museum 

 permitted Mr. Kennedy to bring several specimens to Ithaca and 

 to study others at Pittsburg. Mr. Herbert Campion and Mr. 



F. W. Campion sent several photographs of specimens at the 

 British Museum. Dr. F. Ris of Rheinau, Switzerland, kindly sent 

 proof-sheets of an article expressing his views on the venation of 

 the Zygoptera, and Mr. R. J. Tillyard of New South Wales, Aus- 

 tralia, sent several papers dealing with the same subject and with 

 new and rare Australian Zygoptera. To all of these contributors 

 is due much of the success in the completeness which it has been 

 possible to secure. 



Nomenclature of the Wing- Veins 



The Comstock-Needham system of naming the veins has come 

 into very general use among workers on the Odonata since the 

 Genealogic Study by Professor Needham in 1903; and it is to be 

 retained in all its essentials as presented in his paper, Tillyard, 

 however, (19 14) showed that the vein formerly known as A is in 

 reality partly a secondary structure built back toward the base of 

 the wing from one of the so-called " cubito-anal " cross-veins and 



