1919] Braun: Wing Structure of Lepidopter a 353 



of venation at the base of the wings, they indicate that these 

 conditions are common to all members of the family, although 

 not without modification which may tend to obscure these 

 characters. That such modification does take place in the 

 Micropterygidae, is shown by an examination of the wings of 

 Epimartyria (Fig. 1), which genus, since it precedes the appear- 

 ance of the tongue, must be regarded as a more primitive 

 genus than Mnemonica. In the fore wing, the configuration 

 of these veins is essentially that of Alnemonica. In the hind 

 wing, Cu extends straight to the margin from its point of 

 separation from the 1st A, that is, the "oblique" part of Cu 

 has become so extremely oblique as to be in a line with the 

 longitudinal part of Cu. As is to be shown presently, this 

 differs in no way from the course of Cu of the hind wing in 

 certain undisputed Lepidoptera. In Prodoxus, most of the 

 tracheae are preserved in the extreme base of the wings. Figure 

 2 shows the more general features of the venation, with wavy 

 lines representing tracheas; Figure 3 shows in detail the course 

 of the trachea at the extreme base of the hind wing. In the 

 fore wing the coalesced bases of Cu and 1st A contain a single 

 trachea, which soon divides, one branch following the 1st A, 

 the other branch immediately dividing again, both branches 

 traversing Cu, but soon shriveling up. That portion of Cu 

 between its separation from 1st A and the posterior arculus 

 (which is here transverse and contains no trachea) is evidently 

 homologous with the oblique free portion of Cu in Microp- 

 terygidae and Trichoptera. The tracheee in the base of the 

 hind wing (Fig. 3) show that the relations of Cu to the 1st A 

 are apparently the same as in the fore wing, but the separation 

 takes place extremely close to the base, and the course of the 

 veins is obscured by the tuberosities at the base of the wing. 

 It will be observed that the vein containing a branched trachea, 

 evidently the cubital trachea, is met very obliquely near the 

 base of the wing by a vestige of what appears to be the posterior 

 arculus. The evidence afforded by a study of pupal wings of 

 Prodoxus (Fig. 6) supports the conclusions derived from a 

 study of adult wings. The coalescence of Cu and 1st A, the 

 Z-shaped course of Cu, and the formation of the serial vein are 

 sometimes shown with greater distinctness in the fore wing of 

 Adela bella (Fig. 5), where these features of the venation are 

 almost exactW as in Mnemonica; a similar condition is present 



