THE BRITISH PTEROPHORI. 75 



" digit " in all my descriptions of the perfect insect, calling the 

 part above the fissure the outer digit, and that below the inner 

 digit (see figs. 1 and 2). The hind wings are divided into three 

 distinct feathers; a difference of length, breadth, and coloration 

 of these will often determine the identification of a species. 

 The legs, too, which should always be carefull^y preserved, are 

 sometimes important in separating nearly allied species ; but 

 only in such instances will special reference be made to 

 them. 



The accompanying figures will explain the terms which I 

 shall hereafter use. 



Anyone looking at a collection of our " plumes," and observing 

 the various contour of the wings of the species embraced in the 

 genus Pterophorus, of the British lists, would naturall}^ conclude 

 that they should be divided into several genera ; and so, indeed, 

 they would be in a European collection. There are always 

 objections raised to any innovation in the way of revised nomen- 

 clature, when such change is applied to a species only ; but when 

 the division of a whole grouj) is contemplated it is advisable to 

 proceed carefully. I have therefore thought that, as most collectors 

 use the " Doubleday " list, both for reference and in the arrange- 

 ment of their cabinets, it would be better to defer the breaking up 

 of the Pterophori as arranged in that list, more especially as I 

 shall not be able to describe the species in the order of classifica- 

 tion, but as I can obtain the larvse. It will, however, be as well 

 if I place before your readers the list as generally accepted by the 

 continental lepidopterists. The arrangement is that of Mons. H. 

 D. Wallingren, a Scandinavian entomologist of repute. It is as 

 follows, so far as those occurring in Britain are concerned, and is 

 somewhat modified from Dr. Wocke in Dr. Staudinger's Catalogue 

 of 1871:— 



CN^MIDOPHORUS, Wallgn. AMBI.YPTILIA, Hub. 

 Rhododactylus, W. V. Acanthodactylus, Hub. 



PUNCTIDACTYLUS, Steph. 



PLATYPTILIA, Hub. 



DiCHKODACTYLUS, Muhlig. OXYPTILUS, Z. 



OcHRODACTYLUs, Hub. Parvidagtylus, Haw. 



Bertrami, Roesel. Hieracii, Zell. 



IsoDACTYLUs, Zell. Teucrii, Greening. 



Trigonodactylus, Haw. L^tus, Zell. 



.;; Zetterstedtii, Zell. Pilosell^, Zell. 



