216 BRITISH BUTTERFLIES. 



the Old World. The $ usually provided with a costal fold on the 

 forewing, occasionally with a tuft on one of the wings, and frequently 

 with a tuft of long hairs attached to the hind tibiae, which are usually, 

 but not invariably, furnished with two pairs of spurs. The epiphysis 

 on the front tibia is invariably present. The subfamily Phocidinae 

 is diagnosed by Watson (Proc. Zool. Soc. London, 1893, p. 15) as 

 follows : — 



Antennae with club usually bent into a hook, but sometimes sickle-shaped, 

 always terminating in a fine point. Third joint of palpi, either minute or else 

 porrected horizontally in front of the face (as in the Ismenid section of the 

 Pamphilidae), never curving over the vertex. Cell of forewings always more than 

 two-thirds the length of costa. Discocellulars generally very oblique; nervure 5, 

 slightly nearer either to 4 or 6, never conspicuously close to either. Hindwing 

 frequently with a tail or tooth at submedian ; nervure 5, never fully developed, 

 except in a few Old World genera. 



Subfamily : Hesperiin^e. 



This subfamily contains most of the European Hesperiids — Erynnis 

 alceae, etc., Hesperia malvae, etc., Nisoniades tages, etc. It occurs 

 throughout both the Old and New Worlds, some of the genera being 

 very widely distributed. One of the main features of the subfamily is 

 the presence, in many genera, of a distinct costal fold in the forewings 

 of the $ s, a character, however, that is much more common in the 

 New, than in the Old, World species. In many of the genera, also, the 

 $ is provided with a tuft of long hairs attached to the hind tibiae or 

 fore coxa?. There are, invariably, two pairs of spurs on the hind tibiae, 

 and the epiphysis of the tibiae of the front legs is almost invariably 

 present. The species of many of the genera appear to rest with their 

 wings flat, and not drawn up over their backs as in the Urbicolids. 

 The subfamily is diagnosed by Watson [Proc. Zool. Soc. London, 1893, 

 p. 16) as follows : 



Antennas seldom hooked, occasionally bluntly pointed. Palpi, with the 3rd joint 

 either minute or porrected in front of the face, in the latter case, stout (and not 

 slender as in the Entheid group of the Phocidinae) ; palpi never curving over 

 vertex. Forewing, cell less than two-thirds the length of costa ; nervure 5, 

 invariably nearer to 6 than to 4. Hindwing frequently lobate, but never with 

 a distinct tail or tooth at the submedian ; nervure 5, never fully developed. 



The $ s of most of the species of this group possess, as noted 

 above, a costal fold, often obscure, on the basal half of the forewings, 

 which encloses a silky down composed of delicate scales. Scudder 

 says (Butts, of New England, ii., p. 1639) that " this costal fold is a 

 most remarkable structure, remarkable chiefly because here, and only 

 here, in butterflies, the marginal vein is developed to any appreciable 

 degree; here it is as highly developed as any other vein, and the 

 membrane between it and the costal vein being exceptionally broad, 

 it folds back upon the upper surface so as to lie next the costal 

 vein; so that, though the marginal vein is developed, it does not 

 practically form the margin, but, as in the $ , that function is given to 

 the membrane in front of the costal vein, here doubled upon itself. 

 The purpose of this reflexion of the costal margin is to form an 

 enclosure, within which may be concealed the androconia, probably 

 scent-scales, whose odour is probably so delicate that it needs to be 

 bottled up, as it were, within this concealment, and, indeed, the closure 

 of the fold is so admirable that it is often difficult to tell whether or 

 not there be a fold. Within this fold are several distinct sorts of scales, 



