286 SMITHSONIAN MISCELLANEOUS COLLECTIONS [voL. 48 
while the frenate type of hind wings will serve, unmodified, as 
typical of both heterocerous and rhopalocerous hind wings, the fre- 
nate type of fore wing will by no means serve equally well as typical 
of these fore wings. While the latter will serve as a type of the 
Fic. 33.—Hypothetical type of primitive frenate fore wing. 
frenate heterocerous fore wing, the rhopalocerous type shows a dif- 
ferent condition of radius (text fig. 35). 
Inasmuch as the wide occurrence and the significance of this modi- 
fication of the rhopalocerous radius has been heretofore overlooked, 
I will discuss it in detail. 
In the hypothetical type of insect wing, radius is primarily two- 
branched, forming radius-one and the radial sector. The latter soon 
Fic. 34.—Hypothetical type of primitive frenate hind wing. 
divides, giving rise to radius-two-plus-three and radius-four-plus- 
five. Each of these again divides into two branches, radius-two- 
plus-three into radius-two and radius-three ; radius-four-plus-five into 
radius-four and radius-five. Thus the vein ultimately becomes five 
branched. 
