522 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. 



mined with certainty, shows it to be a Nymphalid, the highest family, 

 "with which the structare of the antenn£e and palpi and the outline of 

 the hind wings, now entirely uncovered, perfectly agree. The first in- 

 ference was drawn principally from the robustness of the body and the 

 form, proportions, and markings of the front wings. The latter are 

 unusually long for a ISFymphalid of this type, have a remarkably straight 

 costa, an outer border bent at the middle instead of far above it, and 

 are possessed of a nearly transverse, median, light-colored belt on a 

 dark ground, a subapical row of small spots depending from the costa, 

 a spot in continuity with them in the upper median interspace, and 

 beyond them, parallel to the outer border, in the costo-subcostal inter- 

 space, a pair of minute spots, — all characters perfectly consonant with 

 Hesperian affinities ; never combined, and each very rare in the Nyni- 

 pJiales. It is not a little strange, however, that while the lorm and 

 markings of the fore wings are hesperidiforra, those of the hind wings 

 are decidedly nymphalidiform. That the exact opposite should be 

 a far more probable occurrence, follows as an assumption from the 

 fact that, as a general rule, the front wings only of the lower Lepidoptera 

 are ornamented, and that therefore the ornamentation of the hind wings 

 is a more recent development. The somewhat variegated markings of 

 the hind wings are indeed similar to what we find in certain Urhicolw, 

 such as PythonideSj but they are far more common in Nymphales^ while 

 the wing-contour is of a high nymphalideous type, quite above anything 

 we ever find in Urbicolce. 



I am at a loss to suggest any really plausible explanation of the mode 

 of development through which the hind wing should have attained an 

 ornamentation consistent with its organization, while the ornamentation 

 of the fore wings, whose structural framework has kept pace with that 

 ■of the hind wings, has not advanced a single step beyond a type common 

 to the lowest family of butterflies. It may, however, be suggested as a 

 mere speculation that the position in which the wings of many Urhicolce 

 are held in repose (the front wings oblique or suberect, while the hind 

 wings are horizontal, and therefore more fully exposed to view) might 

 be productive of such a result. In this case, we should anticipate 

 further indications of such a feature, at least in fossil forms. We are 

 acquainted with the upper surface-markings of both pairs of wings in 

 •extinct butterflies only in Neorinopis sepulta (Boisd.) Butl. and Thaites 

 ruminiana Heer. It had escaped notice in my original study of these,* 

 that when they are compared with living types, indications appear 

 of precisely the same nature, although by no means so conspicuous. 

 The rude patches of color that mark the discoidal area of the front 

 wings of N. sepulta, and the repetition of almost similar, unbroken, 

 transverse bars on the same portion of the front wings of T. ruminiana, 

 when compared with these parts in their nearest living allies, are clearly 



* Mem. Amer. Assoc. Adv. ,Sc. i, 1875. 



