134 BRITISH BUTTERFLIES. 



general less developed than those of U. comma, and by comparing these 

 species one finds that such an unimportant colour-character as a very 

 short silver stripe, may yet constitute a very great and important 

 morphological difference. The tuft of hairs is wanting on the hind 

 tibiae " (Aurivillius). 



Variation. —Viewed from a British, and even from an European, 

 standpoint, one would say that this species was particularly constant 

 in size and markings. For all that, however, there is some variation 

 in tint of ground-colour, in the conspicuousness (or the reverse) of the 

 paler markings, in the extent to which they occupy the basal half of 

 the wings, and in size. On the underside, too. there is considerable 

 variation both of fore- and hindwings, in tint and markings, and here 

 the normal pale spots may be very conspicuous, obsolete, or united 

 into a distinct curved, almost V-shaped, band. Esper figures a ? 

 [Schwett. Eur., pi. xxxvi. (supp. xii.), fig. 1] that has the spotting of the 

 underside of so pale a tint as to make it resemble that of U. comma. 

 But it is in size that the greatest variation exists, and one finds as a 

 rule that the specimens become larger as one goes south and east, e.y. t 

 Sicily, Syria, Japan, etc., developing in the east so greatly in this 

 direction that, at least, two forms have been described as distinct 

 species. Wheeler states that the specimens from the mountains of 

 central Europe are generally darker than those from the plains. 

 Occasional aberrations have been recorded by various collectors, «.//., 

 Buckstone notes a $ with a patch of pale yellow on the forewings 

 between the costaand the oblique discal mark, taken at Purley, in July, 

 1896 ; he also records a smaller and darker $ than usual from Dorking, 

 taken in 1898 (Proc. Sth. Loud. Ent. Soc, 1899, p. 109). Hormuzaki 

 took (Verh. zool.-bot. Gesell., 1., p. 28) a very dark £ at Gastein, 

 and described two other £ s, both only 29mm. in expanse, ground- 

 colour intense dark brown, spots unusually small and distinct = ab. 

 obscura, n. ab. (op. cit., xlvii., p. 167). Henning found a melanic 

 specimen at Frischingwald in Prussia (teste Speiser), and Oberthiir 

 notes (in lift.) an aberration from Vernet, in which the underside of the 

 hindwings has the disc pale, owing to the confluence of all the small 

 spots into a single one = ab. juncta, n. ab. He has also another aber- 

 ration, a $ taken in England, the hindwings of which are very pale 

 without markings. It is difficult to classify the aberrations with 

 which one occasionally meets in Britain and on the continent of Europe 

 where the more typical form occurs. These appear to be — 



(1) The ground colour pallid, the scaling poor, the normally darker areas 

 tending to albinism, and the spots more bleached than usual, giving an impression 

 of pallid uniform colouring = ab. paupera, n. ab. 



(2) Uniform fulvous-brown to outer marginal areas which are darker; the 

 usual pale spots almost or quite obsolete = ab. obsoleta, n. ab. 



(3) Bright fulvous-brown from base to outer marginal area, pale spots almost 

 of same colour; marginal area of rather deeper brown, but not contrasting with 

 spots or median area — sylvanus, Esper. 



Ml The pale spots contrasting strongly with the ground colour which is 

 strongly mixed with fulvous, the darker tint conspicuously present in basal as well 

 as marginal areas. The underside usually fairly marked with upperside design = 

 ab. oppotita, n. ab. 



(-">) The ground colour as in the former, but rather brighter, the marginal areas 

 particularly (lark; the Eorewings with a narrow marginal black line, the hindwings 

 more broadly black-margined; the pale spots full-coloured, bright, but contrasting 

 with ground colour. The underside particularly clearly marked with the upperside 

 design ab. clam, n. ah. 



