HEADLEE]| A STUDY IN BUTTERFLY WING-VENATION 285 
and in the hind wing costa has become a mere vestige in the 
humeral edge of the wing, a frenulum is developed on the humeral 
angle, radius reduced to two branches, and radius-one coalesced with 
subcosta from distal end almost to base (text figs. 33, 34). This 
type is illustrated by Castnia cochrus (pl. Lx, figs. 5, 6). 
3d A 
Fic. 31.—Hypothetical type of primitive lepidopterous fore wing. 
With the exception of the two-rooted condition of the second 
anal vein of the hind wing, all these modifications have been recog- 
nized and discussed by previous workers, so I shall pass them 
without further discussion. Inasmuch as this two-rooted condition 
appears in some of the most generalized Lepidoptera and in widely 
Fic. 32.—Hypothetical type of primitive lepidopterous hind wing. 
separated forms, such as Micropteryx, Prionoxystus robinie, Phassus 
triangularis, and Euschemon rafflesie, it should be figured in the 
lepidopterous hypothetical type (text figs. 32, 34, pl. Lx1, figs. 
710.10). 
Extended study of pupal and adult wings has convinced me that, 
