A GENEALOGIC STUDY OF DRAGON-FLY WING 

 VENATION. 



By James G. Needham, 



Of Lake Forest College, Lake Forest, lllmois. 



INTR0DU(1TI()N. 



This is a new study of one of the oldest subjects in entomology. It 

 \s an application of' the n.ethods of comparative morphology to the 

 interpretation of some external characters universally employed in 

 3y8tematic work upon insects. 



I The richly veined wings of dragon-flies have been carefully studied 

 i)y many able entomologists; their interesting peculiarities are well 

 known -/the homologies of the various parts of the wing have been 

 determined throughout the order; and there already exists a consider- 

 able body of evidence as to the nature and extent of variation in 

 Jvenational characters. There has been as yet no serious effort to use 

 khese characters to determine genealogic succession within the order 

 Sit is the main purpose of this paper to translate the records of natural 

 I selection as written in the al)undant characters of these wings.. 



At the outset I wish to acknowledge ipy indebtedness to the f ollow- 

 ! ino- oentlemen, who have all aided me generously: To Prof. J. H. Com- 

 ' stock, of Cornell Universitv, I am indebted first of all for constant 

 I advice throughout the progress of this study; to Mr. Samu(4 Henshaw, 

 ' of the IVIuseum of Comparative Zoology, for free use of the llagen 

 Collection of Odonata during a stay of two months m Cambridge; to 

 Dr R T. Jackson, of Harvard University, for similar privileges in 

 the study of the fossil Odonata of the same museum; to l^i'- !'• ?• 

 Calvert, of the University of Pennsylvania, for the loan of valuable 

 specimens; to Monsieur R. Martin, of Le Blanc, for the gift ot speci- 

 mens- and to Dr. S. H. Scudder, for the privilege of examining the 

 types of fossil Odonata in his collection, and also some of his original 

 unpublished drawings. 



Proceedings U. S. National Museum, Vol. XXVl-No. 1 331 . 



703 



