Dec 1S97] Grote: Classification of Lepidoptera. 153 



of the three primary veins. Its progress is not uniform, but is evi- 

 denced in different ways. The comparative completion of this effort 

 affords a particular gauge of the standing of the form. The second 

 direction occurs sporadically in very different groups. It consists 

 in an absorption of the branches of the Radius, so that their normal 

 number is diminished. It is probably reminiscent of what has taken 

 place on the hind wings, as we see from Hepialus. When we apply 

 our knowledge of these two tests of specialization to the Day-Butter- 

 flies, we find that the second, or sporadic direction, occurs in the 

 Parnassidae, Pieridae, Lycaenidae, thus independently in otherwise 

 very different groups. It is thus a secondary character and we 

 find it again in a group so dissimilar to the Day Butterflies as the 

 Saturniades, while it is not indicated in the Hawk Moths. The first or 

 general direction of specialization we find indicated by most Lepidoptera, 

 in some of its stages. It is a fundamental movement and has probably 

 a mechanical cause. The Pieridae unite the two directions in a palpa- 

 ble manner, more strongly so than the Lycaenidae, which exhibit, in the 

 Theclinae, the second direction very completely. In the Pierinae 

 {Mancipiinn, Pier is, etc.) the first direction is shown by the transfer of 

 vein IVi, the upper branch of the Media, to the Radius. This state of 

 affairs we find only again so strongly marked in Nemeobius. In the 

 four-footed Butterflies the first direction, or suppression of the Media, 

 asserts itself in the total degeneration of the crossvein ; while the two 

 upper branches of the Media are pulled towards the Radius, the cell 

 opens completely. Thus the Media, as a system, ceases to exist. But 

 in the Nymphalidse, the upper branch of the Media does not become 

 completely absorbed by the Radius, as in the Pieridae, in which latter 

 the cell is never so completely opened as in the former family. Again 

 the second direction is not taken up at all by the brush-footed butter- 

 flies, the Radius remaining generalized, five-branched. Judging 

 from the condition of the hind wings especially, the Agapetinae 

 and Limnadidae are less specialized than the Nymphalidae. The 

 Libytheidae overlap the more generalized Meadow-Browns. The neura- 

 tion of the Libytheidte is almost repeated by the Nemeobiidae, which 

 latter retain no essential wing characters -of the Riodinidse (Erycinidae) 

 or Lycaenidae. I tried to explain its position on the Lycaenid branch 

 by the view that the evolution of the neuration has taken a parallel 

 direction to that of the Pieridae and the four-footed Butterflies. On 

 the neuration by itself we must, and I now do, exclude Nemeobius 

 from the Lycaenid branch. Its junction with this branch must remain 



