( xlv ) 



because they can't help it, and not of any set purpose. 

 Similarly one finds Chrysophanus virgaurese and C. var. rutilus 

 together, and Thecla spini and T. ilicis, and so on. 



The Erehias are perhaps less accidental : several of the 

 " grass " Erehias are generally found together, usually 1 

 imagine fortuitously ; but E. eriphyle, which I found in 

 Carinthia established in localities by itself, rarely occurs in 

 Switzerland except with, and possibly protected by, E. pjharte. 

 Again a few years ago I found at Guarda (Lower Engadine) 

 E. pjharte and E. laanto, forms usually abundantly distinct, 

 equally common on the same ground, and most specimens of 

 such approximating forms as to require some little care to 

 discriminate them. But all these " grass " Erehias are 

 apparently very closely related. This year I found associated 

 in Spain two Erehias that belong to very different sections 

 of the genvis — viz. E, evias and E. stygne. 



In the district examined these were always on the same 

 ground; if one was found you might be sure very soon to 

 see the other. E. evias is an early species. At Digne and 

 Locarno I have found it in April, E. stygne usually at the 

 beginning of July. But these dates must be largely a matter 

 of elevation in each locality. Central European specimens 

 are certainly rarely taken together, and they differ much 

 in habits of flight and especially in size. Ruhl gives stygne 

 as 38-42 mm., and evias 45-49 mm., and though both 

 vary rather more, and evias is usually 50-55 mm., this 

 fairly represents their ordinary relative size. Our specimens 

 from Canales and elsewhere present the two species as 

 very much the same in size, stygne indeed being if anything 

 the larger and closer together in colour and marking than the 

 usual Swiss or French specimens. 



Evias was perhaps a week earlier than stygne, but 

 both flew together all the time we observed them, perhaps 

 about a fortnight. The evias, though not quite agreeing with 

 description, are no doubt substantially of Zapater's var. 

 hispanica, whose leading difference is its smaller size than the 

 type. The stygne are not so large, or otherwise quite the 

 same as my var. bejarensis, but are rather intermediate 

 between the type and that local race. 



