December 1898] THE NEURATION OF RHOPALOCEEA 



391 



the modification of neuration to be observed in the different groups, 

 and I will briefly refer to some lines of specialization observed. 



Group 1. — Generalized Hesperids (Hcspcria) retain five-branched 

 radius in forewings, and three median nervules in very nearly the 

 ancestral position ; but a modification of the transverse 'cell' nervure 

 in the direction of the cubital system forms a three-branched cubitus 

 in forewings (ancestral form is two-branched as in Cossids). Among 



Australian Cossid. 



specialized Hesperids (Pathesperia) one median nervule by incorpor- 

 ation with the radial system forms a six-branched radius in forewings, 

 the middle median nervule and the cell nervule in hindwings dis- 

 appear, and there is a tendency in the middle median nervule in fore- 

 wings to do likewise. (See Dr Grote's figures ; Nat. Sci., vol. xii., 

 pis. i. and ii.). 



The neuration of Lycaenids is similar to that of 

 Pierids, but not identical ; in each group specialization 

 by reduction in the number of radial nervules in fore- 

 wings is observed, but there is this difference, viz., 

 whereas among Lycaenids reduction occurs while the 

 median nervules retain their position and identity as 

 such, the same specialization is observed among Pierids 

 after the incorporation of one of the median nervules 

 with the radial system. Whether it is possible to take 

 into consideration the relative position of the median ner- 

 vules in the forewings of Lycaenids and associate them with Hesperids 

 therefor, my personal observations are not sufficiently extensive to 

 justify an opinion. Certainly the position of the median nervules is 

 extremely alike in each group, and Dr Grote associates them, 

 having observed also the tendency among Lycaenids to lose the middle 

 median nervules in the same manner as do Hesperids. This, so far as 



Chrysophanus 



pklaeas 

 (Lycaenid). 



