SCUDDER ON TERTIARY INSECTS. 521 



Hind wiDgs shaped somewhat as in Rypanartia, the costal border 

 beyond the great rounded prominence of the extreme base being very 

 gently convex, the outer margin full on the upper half, the upper outer 

 angle broadly rounded; the upper median nervule is developed in the 

 middle of the wing into a long, slender, tapering tail, and the lower half of 

 the wing is strongly crenulate, and especially roundly excised in the lower 

 median interspace and lobed on the lowest median nervule; the lower 

 outer angle is well rounded; the inner margin plainly forms a gutter 

 for the reception of the abdomen. The costal and precostal veins are 

 very doubtful, being exceedingly obscure on the specimen ; but the 

 former apparently arises from the common stem of the costal and sub- 

 costal veins at right angles to it shortly beyond the base, and then curves 

 strongly outward subparallel to the costal margin, striking the latter 

 in the middle of its apical half; while the precostal is a simple recurved 

 vein, directed inward and forward at the sharpest point of the costal 

 curve. The subcostal vein is peculiar in that its first branch, origina- 

 ting only a little beyond the costal, approximates so closely to the costal 

 margin as to strike scarcely outside of the upper outer angle of the 

 wing, a place usually reserved for the apex of the costal vein ; the sub- 

 costal forks again, scarcely more than one-quarter way from the base of 

 its first branch to the margin, the middle branch continuing the curve 

 of the main stem, and the lower branch diverging very gradually from 

 it, and widely distant from the median vein. The main stem of the latter, 

 with its upper branch, forms a gentle sinuous curve scarcely approach- 

 ing the subcostal vein (the cell being open), and emits its first branch 

 in the middle of the cell, or scarcely more than half-way from the base 

 to its final divarication. Thislatter is unusually slight, the middle branch 

 keeping throughout very close to the upper and distant from the lower 

 branch. The submedian strikes the angle of the wing as far from the 

 lower branch as it is from the middle branch of the median. The in- 

 ternal nervule cannot be determined. 



The abdomen is full, with the third and fourth joints longest, the 

 whole nearly twice as long, and in the middle fully as broad as the 

 thorax. 



This is the first butterfly that has been found fossil in America, and 

 as only nine species are known from the well -worked Tertiary strata of 

 Europe, it may properly be esteemed an especial rarity. Besides this 

 it has a double value : first, in that it is far more perfect than any of 

 the European specimens (nearly all of which I have seen) ; and, second, 

 in presenting, as none of the others do to any conspicuous degree, a 

 marked divergence from living types, combined with some characters 

 of an inferior organization. When first received, the tails of the hind 

 wings and the tips of the antennae were hidden by flakes of stone, and 

 it was taken, both by myself and by every entomologist to whom I 

 showed it, to be a Hesperian, the lowest family of butterflies. The neu- 

 ration, however, which, although mostly very obscure, can be deter- 

 Bull. iv. No. 2 14 



