394 NATURAL SCIENCE [December 



Heterocera). Here also we may refer to the features A, B, C of Anosia 

 (evidently overlooked by Dr Grote) ; as already stated, these are 

 not to be observed among specialized Nymphalids. Now, the 

 cubitus-anal connection, short anal nervure of the forewings, and 

 subcostal-radius connection in the hindwings of Papilionids are 

 generalized features, homologous with the features A, B, C of Anosia, 

 modified and lost in other groups of Ehopalocera ; it is impossible to 

 regard them in any other light. In this respect then Papilionids 

 approach the generalized Nymphalids. 



Eeaction of modification appears to me to have caused different 

 lines of specialization of neuration in the Lepidoptera, consistent 

 with adequate support of the wing membrane, and the develop- 

 ment of wing area and shape ; for example, it seems that modifi- 

 cation of neuration has been rapid in the case of Opostega 

 crepusculella, which is not highly specialized in wing area and 

 shape as compared with primeval Trichoptera-Lepidoptera, but 

 the neuration has been reduced to several simple (unbranched) 

 nervures. The area and shape of Ehopaloceran wings are, however, 

 more highly specialized, and the modification of neuration — particu- 

 larly of the forewings — has been less rapid. If we draw the line 

 separating primitive Ehopalocera from the mass of primaeval 

 Lepidoptera at Hesperids, then we have the fact that no 

 Ehopalocera possess the basal portion of the median nervures, 

 and this loss we may assume to be the point of separation 

 (granting, also, modification of hindwing neuration, which every- 

 where in the Lepidoptera has preceded that of the forewings). 

 Next we have noted the formation of three-branched cubitus 

 in the forewings, by the incorporation of one of the median 

 nervules with the cubital system in Hesperids and subsequent 

 specialization in the direction of Lycaenids. In another direction, 

 apparently at some distance from Hesperids, we note that a three- 

 branched cubitus is a fixed feature in the neuration of Nymphalids' 

 forewings, that no movement has taken place in the position of the 

 other median nervules, and very little subsequently among Nym- 

 phalids and Satyrids. But as the Pierids separated from the 

 Nymph alid-Pierid stem, the median nervules moved towards, and 

 one became incorporated with, the radial system. The cubitus 

 ' blotch ' and rudimentary anal nervure of the forewings and the 

 subcostal- radius connection in the hindwings of Anosia point to the 

 possession of the Papilionid cubitus-anal connection, two anal 

 nervures in the forewings, and a subcostal-radius connection in the 

 hindwings by those primaeval Ehopalocera from which the Nym- 

 phalid-Pierid groups originated ; and another important fact is that 

 at this point two anal nervures in the hindwings were retained 

 (as in Hesperids). Next in sequence come the Papilionids, in 

 which movement of one of the (Nymphalid) median nervules forms 



