58 FOSSIL BUTTERFLIES. 



uniform curve with the outer border, which is almost entire as in Parnassius (PI. 

 Ill, fig. 5), rather than as in Thais (PL III, fig. 4), strongly arched, especially 

 near the last median nervnle, and angulated below where it meets with the regu- 

 larly and broadly concave inner margin. 



In the neuration of the fore wings (PI. Ill, fig. 1) this genus is peculiar for 

 the shortness of its cell, which is less than half as long as the wing, and is broad- 

 est in the middle of its distal half, beyond which it narrows rather rapidly. The 

 costal nervure terminates a little before the middle of the outer two-thirds of the 

 costal border. The subcostal nervure emits two superior branches before the cell ; 

 the first is thrown off near the middle of the outer half of the cell and teraiinates 

 as far beyond the tip of the costal nervure as it is beyond the middle of the costal 

 border; beyond the emission of the first superior nervule the subcostal nervure 

 curves downward away from the costal nervure, with which it had hitherto been 

 parallel, and throws off the second superior nervule shortly before the apex of the 

 cell; this nervule terminates exactly at the apex of the wing, but, just before the 

 tip, divides, sending a short branch to the outer border; about two-fifths of the dis- 

 tance from the tip of the cell to the outer border, the subcostal nervure divides 

 into two branches which reach the outer border near the middle of its upper half; 

 the inferior subcostal nervule leaves the nervure nearly at right angles, but almost 

 immediately turns and runs subparallel to it and its lower ultimate branch. The 

 median nervure throws off its first nervule a little beyond the middle of the cell ; 

 its second midway between this and the base of the fourth, and the third midway 

 between its two neighbors ; beyond the emission of the second nervule the nervure 

 bends upward, and still more on throwing off the subsequent one; the first two 

 nervules are straight, the upper two arched, and the base of the last is united to 

 the short basal fragment of the inferior subcostal nervule by a curving vein open- 

 ing outward, whose general course is nearly at right angles to the costal border. 



In the hind wing the relation of the cell to the length of the wing is as in the 

 front pair; it is broadest at the first divarications of the bordering nervures and 

 narrows rapidly beyond. The first branches of the subcostal and median nervures 

 are emitted near the middle of the distal half of the cell, and that of the subcostal 



