202 BRITISH BUTTERFLIES. 



Belg.," p. 222 (1902); Fount., " Ent.," xl., p. 102 (1907); Tutt, " Ent. Rec," xxi... 

 p. 59 (1909). Aegon var., Obth., " Etudes," xxi., pp. 28-29 (1896).— This variety 

 appears sufficiently remarkable to be described. The $ differs only from the 

 ordinary type by its rather darker tint of blue, and by a rather wider white fringe ; 

 but the ? is always brown with the base and the disc of the four wings of a very 

 brilliant blue, the fringe wide, of a yellowish-white, not chequered. It is the under- 

 side of this variety, and especially that of the ? , however, that offers the chief 

 character of this race. It recalls the modification that Lycaena agestis undergoes 

 in the mountains of Scotland, a modification that has received the name of artaxerxes. 

 The underside of the Corsican aegon is of an uniform grey-brown ; the many discal 

 spots are no longer black, but of a tint hardly darker than the ground colour, from 

 which, however, they are clearly cut off by a white margin that encircles them. 

 The discal spot of the forewing is much larger than in other races. The larva 

 lives in June on a species of Astragalus. The imago is common in the mountains, 

 where the plant, serving as food for the larva, grows in abundance. It occurs from 

 the end of June until Axigust, according to altitude (Bellier de la Chavignerie) . 



This is a very marked and special race. The upperside of the J 

 is only narrowly margined on the forewings with black, and on the 

 hind wings with interneural spots, whilst the $ is, as noted above, 

 strongly suffused with blue. On the underside, however, instead of 

 the characteristic black spots, their position is clearly outlined with 

 well-marked white rings enclosing merely rather large portions of the 

 unmodified ground colour. Oberthiir says (Etudes, xx., pp. 28-29) 

 that " the Corsican race is very curious ; above, the 2 s are blue, as in 

 calliopis, and below, the ordinary spots are brown, of the tint of cafe- 

 au-lait, similar to the ground colour of the wing, instead of being" 

 black." Powell writes (in litt.): " Even in the freshest specimens the 

 underside has a rather worn appearance, owing to the faded look of 

 the spots, which are often not much darker than the ground colour, 

 especially in the ? s, although always surrounded by w r hite rings. 

 The 2 s are often much suffused with blue above, with the marginal 

 row of orange crescents very feebly indicated or absent on the fore- 

 wings, and rarely strongly marked on the hindwings ; the crescents 

 are frequently suffused and swallowed up by the broad black margins. 

 This variety was in great abundance on the top of the Col de Scalella, 

 between Bastelica and Bocognano, alt. 1173m., July 13th-24th, 1905, 

 on rough pasture land with short grass, dwarf juniper bushes, low- 

 growing thistles with large flowers, and a sort of lemon-thyme, the 

 flowers of which are very attractive to this ' blue.' The insect occurs 

 only a few metres below the summit of the Col, north or south ; the 

 chestnut forest begins a little below the Col on the north side, and the 

 variety occurs in diminishing numbers down to the first trees ; on the 

 south side it is much scarcer, and one sees no more of it as soon as 

 the bracken and heather become abundant. Here it is replaced by the 

 scarcer, but more widely distributed, Corsican form of P. argyrognomon, 

 which is to be had all over the Bastelica region." /'. argus var. Corsica, 

 is also found on the Vizzavona Pass. Miss Fountaine notes (Ent., 

 xl., p. 102) that the var. Corsica was only taken in 1906, on the very 

 top of the Col de Vergio, about 5000ft., in July, where it was extremely 

 plentiful. Actual specimens of this form in the Brit. Mus. coll., are 

 noted as having been taken between June 22nd-July 21st, 1893, at La 

 Foce, June 15th, 1893, at Tattone (Yerbury). 



0. vnr. maeseyi, Tutt, " Ent. Roc," xxi., p. 58 (1909). Corsica, Massey, 

 "Ent. Rec," vii., pp. 127 et so,. (1895); Murray, "Ent. Rec," ix.,p. 294 (1897).- 

 <S 8 varying in colour from those having a distinct argus (aegon) tint (with just a 



