HOMOLOGIES OF THE WING VEINS OF THE APHIDIDiE, 

 PSYLLIDiE, ALEURODIDAE, AND COCCID^* 



Edith M. Patch. 

 INTRODUCTION AND GENERAL CONSIDERATIONS. 



This study of wing venation was undertaken in the hope 

 that it might, for the one small group of Homopterous insects 

 it concerns, supplement in some slight measure other work in 

 wing-\'ein homologies which has been so vital a problem for insect 

 phylogeny. 



The incentive to this study is to be found in "The Wings of 

 Insects" by Comstock and Needham. The choice of the parti- 

 cular group here considered was due to a personal interest in 

 aphids and to the fact that the homologies of the wing-veins 

 of this family were at that time practically untouched. 



From the first the work has been under the direction of the 

 Department of Entomology, Cornell University and it is a pleasure 

 to acknowledge the kindness of Professor Comstock during my 

 association with this department as a student, and the patient 

 aid and constant interest and sympathy in my task of Doctor 

 MacGillivray. 



To Professor Oestlund at the University of Minnesota is due 

 thanks for the determination of certain species of aphids which are 

 included in this study and for the personal interest with which 

 he has anticipated the results. 



Although the work has been entirely under the supervision 

 of the Department of Entomology, Cornell University, the great 

 bulk of the data has been accumulated at Orono, Maine, instead 

 of Ithaca, New York. Several months of each winter during the 

 grogress of the problem, however, have been spent at Cornell in 

 revising data and in such consultation as has insured against 

 certain misinterpretations and other errors due to inexperience 

 in this type of work. At such times the essential points have been 

 in so far as is possible with the greenhouse aphids available, 

 verified while in residence in Ithaca, and the work with the Coc- 

 cidae and Aleurodida? has been done in the Entomological labor- 

 atory at Cornell University. 



Since 1903 each season's collection of aphids in Maine with 

 detailed notes has given me a very fair idea of where to secure 



* A contribution from the Entomological Laboratory of Cornell University, 

 and Papers from the Maine Agricultural Experiment Station ; Entomology No. 33 



lOI 



