258 BRITISH BUTTERFLIES. 



This only differs from the last in the ground-colour being grey- 

 instead of white. The specimen figured was taken by Austin at 

 Folkestone, in 1890, and was in the Briggs coll. 



d. ab. antero-obsoleta, n. ab. — Specimens showing obsolescence of the spotting 

 on the forewing only. 



This may occur either in the marginal or discal row of black spots. 

 In the former case, which is common in northern England, it is one of 

 the transitional forms to var. artaxerxes. In the latter case the black 

 spots and their white circle tend equally to disappear. The partial 

 absence of the discal row, as exemplified in the very frequent loss of 

 the geminated spot, and the almost universal failure of -the costal 

 spot, has already been remarked upon (p. 233). Further obsolescence 

 on the forewing is rare, but according to Hodgson not more so, in 

 Britain, than on the hindwing. 



e. ab. postico-obsoleta, n. ab. — Specimens showing obsolescence of the spotting 

 on the hindwing only. 



The commonest form of obsolescence on the hindwing is probably 

 the absorption of one of the spots of the discal row in the light wedge- 

 shaped streak, and next to this, the absence of the 3rd, or less 

 frequently the lowest, basal spot. Others of the discal series, 

 especially the second from the costa and the lowest, are also often 

 absent, especially in the mountain specimens, but a greater degree of 

 obsolescence is rare. 



In the Brit. Mus. coll. is a specimen from Borjoni, from collection 

 of Grum-Grshimailo, in which the obsolescence of the hindwing 

 spotting is very marked, though the discal row is not entirely absent.* 



^. ab. obsoleta, n. ab. [Hodgson, "Ent.," xli., p. 68 (1908), without descrip- 

 tion.] Specimens showing obsolescence of the spotting on both wings. 



This form, differing from abs. deleta and i in punctata in the fact 

 that the spotting is not absent but only obsolescent, is, according to 

 Hodgson, less uncommon than either of the two last described, at any 

 rate in Britain. Beyond a combination of the slight obsolescence 

 common in these two aberrations, the form is, we believe, extremely 

 rare. Courvoisier (Mitt. Scliweiz. Gesells., xi., p. 19) mentions two 

 specimens, both $ , in which this tendency is carried to an unusual 

 extent. 



7}. ab. parvipuncta, n. ab. — Specimens in which the spots are unusually small. 



This is a common form of aberration, especially in specimens 

 belonging to the allous, semi-allous, and alpina forms. The spots on 

 the hindwing particularly are often minute. 



6. ab. crassipuncta, n. ab. — Specimens in which the spotting is unusually 

 large. 



This form is, according to Hodgson, less common in Britain than 

 the last. It is, however, far from uncommon in the southern races, 

 and is especially apt to recur in var. crafnera. Hodgson notes that it 

 is almost always produced by the enlargement of the black pupils at 

 the expense of the white rings, and that, except in the case of a tendency 

 towards striate forms, it is very rarely that these latter are noticeably 

 enlarged. 



* I have a large & from Roccaraso, and a small one from Villalago, both in 

 the Abbruzzi, in which only three and four spots of the discal row respectively are 

 left.— (G.W.) 



