1899.] GROTE — SPECIALIZATIONS OF LEPIDOPTEROUS WING. 11 



what I consider to be the undoubted relic of a true longitudinal 

 vein, taking an opposite direction to vein viii, and running out- 

 wardly and downwardly to the inner margin of the wing, and 

 which I have called vein ix. If the view is accepted that vein viii 

 originates in a splitting of vein vii at base, then it might be held 

 that this splitting occurred after vein ix had been gotten rid of, and 

 that consequently butterflies with vein viii represent a succeeding 

 stage in this respect. I believe to have shown that, in certain of 

 .the more specialized of the Hesperiades, vein viii gradually fades 

 out. In the Nymphalids I find very faint traces of it only in cer- 

 tain Argynnin^. I have found no trace of it in any Satyrid. It 

 has vanished in Leptidia, is present in Pseudopontia, and, while 

 strong in Colias, is fainter in some of the other Pierinae. Certain 

 Lycsenidae appear to have lost it, or it is very faint, and this may 

 be the case also with some Hesperians, though in this latter group 

 it is usually quite legible. Conceding its variability, no better 

 evidence perhaps of its power of extinguishment can be offered 

 than that it is strongly marked in Libythea and Lwmas, and that it 

 is incomplete in the related Heliconius. 



Let our theories as to viii be as they may, one thing seems clear : 

 that no traces of vein ix of the Papilionides have been found in 

 the Hesperiades, and that this latter group is held together, as 

 opposed to the former, by the negative character of its absence. 



My attempt therefore, to connect the Papilionides with the rest of 

 the diurnals, has failed. In my first draft of the genealogical tree 

 (1896-189 7), and which is still pinned above my desk, I supposed 

 that the point of contact might be with primitive forms, less 

 specialized than the Hesperians. These would have all exhibited 

 vein ix, which the Papilionides had retained, while the other 

 ascending branch had lost it. I reproduce here this sketch, the 

 readier since Dr. Chapman, in letters to me, has queried whether 

 an analogous scheme might not work. 



