NOMIADES. 109 



Lyc(E7ia arion, Newman, Brit. Butterflies, p. 136(1881); Lang, 



Butterflies Eur. p. 133, pi. 32, fig. 5 (1882). 

 Van Polyommatus alcon, Stephens, /. c. p. 88 (1828). 



The Large Blue is common throughout a great part of 

 Europs and Northern and Western Asia, and on the Con- 

 tinent is frequently found in company with three or four other 

 closely-allied species which do not occur in England. One 

 of these, N. arms (Von Rottemburg), is a very dark-coloured 

 species. Like -^V. semiargus, it was always very local in Eng- 

 land and Wales, the principal locality for many years having 

 been Barnwell Wold in Northamptonshire, where it is said to 

 have been finally exterminated by a dealer. As, however, it is 

 fond of waste ground, the advance of cultivation has been its 

 real enemy ; for it appears to have been taken occasionally in 

 most counties in the southern half of England. But for many 

 years it has been rapidly disappearing, and is apparently on the 

 verge of extinction as a British species, though it still lingers 

 on in certain restricted localities in Devonshire and Cornwall. 



The Large Blue measures an inch and a half, or rather more, 

 across the wings, which are of a purplish-blue, with rather broad 

 black hind-margins, and the costa of the hind-wings black. The 

 fore-wings have a black discoidal lunule, beyond which is a row 

 of rather large black spots. The fringes are white above, but 

 spotted with brown on the nervures beneath. The hind-wings 

 have a sub-marginal row of black spots, and in some varieties 

 of the female are spotted almost as in the fore-wings. The 

 underside is greyish-brown, greenish towards the base, with dis- 

 coidal lunules, and a central row of black eyes beyond, ringed 

 with white, one or two more or less distinct rows of sub-marginal 

 spots, and some additional eyes towards thj base of the hind- 

 wings. The Butterfly appears in July, and is fond of settling 

 on the blossoms of wild thyme, on which the larva, which is 

 imperfectly known, feeds. 



