WING STRUCTURE OF LEPIDOPTERA AND THE PHY- 



LOGENETIC AND TAXONOMIC VALUE OF CERTAIN 



PERSISTENT TRICHOPTEROUS CHARACTERS. 



By Annette F. Braun, Cincinnati, O. 



I. Introduction. 



II. Wing Structure. 



(a) Venation. 



(b) Mode of insuring synchronous action of fore and hind wings. 



(c) Distribution of fixed hairs. 



III. Summary and Conclusions. 

 IV. References. 



I. Introduction. 



It is agreed that- the insects constituting the two orders 

 Trichoptera and Lepidoptera respectively are closely related 

 genetically. All insects included in these orders have the same 

 general and characteristic type of venation, which in the more 

 primitive forms closely approaches the hypothetical primitive 

 type as figured by Comstock. It is the problem of determining 

 where the line of division shall be drawn between Lepidoptera 

 and Trichoptera which presents difficulties. According to the 

 usually accepted classification, the Micropterygidae are regarded 

 as the most primitive group of Lepidoptera, from which all the 

 other Lepidoptera have been derived. This group more closely 

 resembles in venation and mode of uniting the fore and hind 

 wing in flight the more generalized of the Trichoptera than it 

 does any other group of insects, evidently approaching the 

 stem form from which both groups have been derived. On 

 the basis of certain common and characteristic features in 

 venation, and the identical structure of the fibula in both, 

 Comstock ('18) removes the Micropterygidae from the Lepi- 

 doptera, confirming his conclusion by the results of Dr. T. A, 

 Chapman's studies of pupae, and makes them one suborder of 

 the Trichoptera, the Micropterygina, the members of Tri- 

 choptera as usually recognized constituting the other suborder, 

 the Phryganeina. 



In addition to the Micropterygidae, there is another group 

 of moths, the Nepticulidae, the more generalized members 

 •of which possess a fibula identical in structure with that of the 



349 



