1900. | GROTE—THE DESCENT OF THE PIERIDS. 33 
Gen. Defias Hiibn., 1816. 
Type: D. egialea. 
Delias egialea. 
Radius three-branched ; #1 from above cell in original position ; 
#2 ashort fork out of 3-5 before apices. Cell closed, vein be- 
tween J/2 and 4/3 somewhat degenerate; J/2 radial; J/t from 
radius immediately beyond cell. Second anal with basal fork. Hind 
wings with pointed, outwardly curved humeral spur; cell closed, 
vein somewhat degenerate; Sc. apparently solid at base. Differs 
from /iccarda in the position of J/1, which springs from radius 
quite close to the cross-vein beyond the cell, and hence is the more 
generalized form. 
Gen. Pereute H.-S., 1867. 
Lype.: EP: callinice. 
Pereute callinice. 
Radius three-branched ; #1 only from above the cell, but not in 
original position, being outwardly removed near to cross-vein; 2 
a short sinuate branch anastomosing with Ar just before apices, 
thus a long supradiscal cell is formed, closed outwardly by R2. 
Cell closed, vein hardly or not degenerate; J/2 central; J 
from radius about one-fourth of distance between cross-vein and 
external margin, herein resembling Prccarda. Second anal vein 
with thin fork at base. Hind wings with abbreviate humeral spur, 
not pointed, appearing turned to base of wing ; cell closed, vein not 
degenerate ; Sc. apparently solid at base. 
This genus, except for the position of costal vein of secondaries, 
would appear as a lateral specialization of Defias. The fusion of 
#2 with A: at tip of wing is so extraordinary that I should like to 
examine more material than is now accessible. Specialization is 
shown by the outward movement of A1 and J7r. On the straighter 
and rather longer portion of the cross-vein between 47/2 and radius 
are too very slight inward projections showing where the vanished 
base of the median system joined on. In Precarda and Deltas 
these projections are barely indicated in the same places by a slight 
unevenness of the vein. This fact, among others, might show that 
the three genera are related, since in Perhyédris there is only one 
projection in the middle of the shorter discoidal vein between 
M2 and the radius. In both this form and the more generalized 
PROC. AMER. PHILOS. SOC. XXXIX. 161. Cc. PRINTED MARCH 19, 1900. 
