1900.] GROTE—THE DESCENT OF THE PIERIDS. 51 
only represent unequal stages in the normal course of specialization, 
preserving an identity of general character which renders the idea 
of different genera difficult. It must be also borne in mind that all 
the species have not been compared, and the chances seem to be 
that among a number of forms agreeing so well externally, similar 
characters to those here used will occur, still further increasing the 
number of genera. 
In the comparative length of the fork #3 with #4 + 5 the genus 
Catopsilia is the more specialized. 
Gen. Callidryas Boisduval and Le Conte, 1829. 
Type: C. eubule: 
Callidryas eubule. Proc. Am. Pui. Soc., Vol. xxxvii, Pl. ii, Fig. 
Io (neuration). 
Rz has strayed still further from cross-vein than in the two pre- 
ceding types. The fork of 3 with R4-+ 5 is much as in 
Phebis ; on the other hand 4/1 has progressed further up the vein, 
intermediate in position between Cafopsilia and Phebis. Perhaps 
this type is really intermediate, although the .view that it is the 
more generalized is tenable. The base of the humeral spur is 
developed as in Pheéis, which latter may more nearly represent the 
type from which the others and the whole Eurymini have sprung. 
We now come to what appears to be a lateral specialization of 
Catopsiliia or Phedis. 
Gen. Parura Kirby, 1896. 
Type: P. cipris Fab. nec Cramer. 
—= Metura Butler, 1873, preoccupied. 
Parura cipris. 
Differs from the types included under Casopsitia by the hind 
wings being strongly produced at anal angle. The condition of the 
shifting branches nearly reproduces the condition of Phadis. The 
humeral spur is incomplete. 
I have now exhausted my material of the types of genera in the 
Pierids. It has been sufficiently extensive, I hope, to have allowed 
me to sketch the group and to lay down for the first time some safe 
conclusions upon the neuration. That more remains to be done I 
am fully aware, nor do I insist upon minor points, liable to be 
modified from greater material. I have wished mainly to supply a 
neurational basis for the generic types examined and as a general rule 
