PLEBEIUS ARGUS. 208 



trace of red in it), to the blue which characterises argyrognomon. The dark 

 marginal border is narrow, and, in some specimens, restricted to a line line, with 

 dark nervures showing on the outside of the wing. The hindwings in all the 

 specimens present a more or less complete row of marginal black dots, separated 

 by the fine black nervures, and, in some specimens, edged externally with paler — 

 one specimen shows a pale coloration along the costa, and at the upper part of the 

 outer margin of the hindwing. The undersides of the forewings of the cf s may be 

 described as pale grey with blue bases, with but little orange on the marginal 

 border, and with slight variation in the size of the spots forming the transverse 

 angulated row crossing the forewings. The hindwings are characterised by a white 

 band between the marginal row of orange spots and the transverse row of black 

 spots, the latter of which in the antepenultimate spot shows some tendency to vary, in 

 some specimens being much higher than, in others more in a line with, the remainder. 

 The upperside of the ? s is most remarkable, the forewings being blue at the base, 

 the colour extending to the centre of the wing, and reappearing again as a trans- 

 verse shade reaching from the costa to the inner margin, leaving the broad brown 

 outer marginal band, which is so characteristic of the S P. argus (aegon). Faint 

 traces of orange spots are sometimes present in this outer marginal band. The 

 hindwings are shaded entirely with blue, which is of two tints, as in the J s, the 

 more purple argus (aegon) tint and the bluer argyrognomon tint, the latter very 

 bright and characteristic ; a series of marginal spots is present in all the 

 specimens, but the quantity of orange present is distinctly limited. The under- 

 sides of the ? s are characterised by the distinct white band which traverses 

 all the wings between the orange marginal band and the transverse row of black 

 spots, and also by the strong development of the silver studs in the orange bands. 

 There is also some variation in the transverse band of spots on the hindwings, the 

 antepenultimate spot being well raised out of the level of the others (an argus 

 character) in some specimens, whilst it is almost in a line with the other spots (an 

 argyrognomon character) in other specimens. In colour the undersides are pale 

 grey with a brownish tinge, but with scarcely a trace of greenish-blue at the base 

 (completely absent in some) (Massey). 



Owing largely to our suggestion, this race was first described by 

 Massey as var. Corsica, a race very similar on the upperside, very dis- 

 similar on the underside. The race occurs on the " mosses " that are 

 found on the Westmorland and Lancashire borders, and is to be 

 captured in both counties. Massey says that the insects occur only in 

 the wettest part of the "mosses," are extremely local, and fly very 

 little ; he has found them only on very limited parts of the mosses, 

 but as there is an enormous tract of country similar to that in which the 

 insect occurs, it is possible that it is really widely distributed there. 

 It was first recorded from these mosses by Hodgkinson, who captured 

 it at Witherslack, on July 21st, 1856, and then in profusion on July 

 14th-15th, 1861, at Whitbarrow Scar ; then it seems to have been 

 overlooked till taken in the Witherslack Mosses by Massey, on August 

 1st, 1892, July 14th, 1893, July 20th, 1894, and July 14th, 1895. 

 Crabtree took it in fine condition, on July 17th- 18th, 1897, July 29th, 

 1898 ($ s only, a late season, and not fully out), July 20th, 1902, (<?s 

 only, and these only just commencing to emerge), and on July 20th- 

 21st, 1906. Murray notes that, in 1897, he found them flying among 

 a very low species of rush about 3ins. high, in a place where trefoil 

 does not seem to occur. Massey says that, he has never seen a ? of 

 the uniform brown shade, usuallv characteristic of the south of 

 England specimens ; it is quite unknown on what the larvae feed in 

 the Witherslack district, but there is an abundance of Ornithopus 

 perpusillus on the mosses. 



X- var. cretaceus, Tutt, " Ent. Rec," xxi., pp. 58-59 (1909). JEgon, Barr., 

 " Lep. Br. Isl.," pi. xi., fig. 1 (1893). Hypochiona, Jones, "Ent. Mo. Mag.," xli., 

 p. 254(1905); " Proc. Ent. Soc. Lond.," p. xlvi (1905).— <? . Bright blue, dark 

 margin of forewings narrow or absent (sometimes quite pallid), discoidal lunule 



