1898.] GROTE — SPECIALIZATIONS OF LEPIDOPTEROUS WING. 27 



pendent of relative breadth or shape of wing we have in the latter a 

 simpler pattern, the veins more equidistant, an indisposition to fuse 

 and furcate shown by the retention of a central position by vein ivj ; so 

 that as the suppression of the media takes its course this branch 

 tends to degeneration in situ, from resisting the attraction of either 

 radius or cubitus. As opposed to this we have a willingness in 

 the Pieri-Nymphalidae to preserve vein iv.,, which latter tends every- 

 where to become radial, except in the isolated case of Leptidia, 

 where it becomes cubital. We have a spreading of the veins and 

 abundant traces of unequal specialization. Except in the lycaenid 

 reduction of the radial branches, the Lyc?eni-Hesperiad^ offer few 

 neurational changes to aid our formation of classificatory categories ; 

 the Pieri-Nymphalidse plenty. United by the presence of the loop- 

 ing vein viii, or its traces unequally expressed and sometimes quite 

 vanished, the Hesperiades offer in this way two groups characterized 

 by the peculiar neurational wing pattern ; giving us also an instance 

 of parallelism in specialization, in that the Pieridae sustain an 

 analogous position with regard to the ''brush-footed" butterflies 

 (Nymphalid?e, etc.), to that the Riodinid-Lycsenids show with re- 

 spect to the Hesperids or ''Skippers." In both these groups the 

 reduction of the radius takes place; the Pierids still showing phases 

 embracing and intermediate between the five 'and three-branched 

 radius, while no five-branched Lyc?enid is yet known to me. Thus 

 the gap in the Lycaeni-Hesperiadse between the subgroups is greater 

 than that between the subgroups of the Pieri-Nymphalidae. But the 

 fact that the reduction of the radial branches has been indepen- 

 dently taken up by the two main wing groups of the Hesperiades 

 comes clearly out. I have been unable to find any characters which 

 will always distinguish the neuration of the Hesperiades from the 

 moths. Not so with the Parnassi-Papilionidae, a distinct major 

 division entirely left out of sight in the present studies. 



Having thus endeavored to trace the outlines of the neuration of 

 the Pieri-Nymphalidae as a whole and to enable the reader to grasp 

 more or less fully the wing structure of this waste of butterflies, we 

 may more in detail compare the wings of the " Whites " with those 

 of the other butterflies in their group. That the radius is special- 

 ized in the Pieridae and generalized in all the other families is the 

 first and obvious difference, one which strikingly throws the bal- 

 ance of specialization to the side of the " Whites." So that in this 

 direction of secondary specialization, which the Pieridae share with 



