10G BRITISH BUTTERFLIES. 



that, in Dorset, both sexes show great variation in size, whilst some 

 of the $ s are much more thickly powdered with silvery-blue scales 

 than others, and these blue scales are always more numerous on the 

 fore- than on the hindwings. Dennis has recorded the capture of 

 exceptionally blue-powdered examples at Horsley, and Adkin observes 

 that, in 1904, the $ s taken at Eastbourne, are exceptionally 

 strongly blue-scaled, suggesting a seasonal difference here, whilst 

 Main notes that those taken at Folkestone the same year exhibited 

 considerable variation in this respect (['roc. 8th. Loud. Ent. Soc, 

 1905, p. 70). As to local variation, Wilkinson states (in litt.) that 

 the $ s from Gelt and the Newbiggin Woods are very much bluer 

 than the Wreay ones, whilst Main also notes large specimens from 

 Cumberland (Ent., xxxv., p. 327). Wocke records (Stett. Ent. Zt<j., 

 xxv., p. 175) the Scandinavian examples captured at Hamar am Mjosen, 

 as being quite similar to the German specimens, only the S s some- 

 what more richly dusted with blue on the upperside. Rebel notes 

 (Lep. Balkayis, p. 186) that the coloration of the Bosnian and 

 Hercegovinian examples is dark brown, the $ s most strongly dusted 

 with blue towards the base of the wing, the black spots on the under- 

 side strongly developed, and adds that these large specimens have often 

 erroneously been referred to sebrus (del. Homeyer). Fuessly's original 

 description is of an uniform fuscous form, possibly, therefore, a 2 , 

 and this appears to be so also with the Fabrician alsus, but Hiibner's 

 alsus (fig. 279) shows slightly the blue scaling at the bases of the 

 wings characteristic of the normal $ . Aigner-Abafi records breeding 

 very large, deep black, examples from larvae found feeding in the pods 

 of Colutea arborescens, but others bred by Szepligeti, from larvae on 

 seed-heads of Sanf/uisorba, were quite normal. The $ s of the Thibetan 

 and Mongolian race var. magna, Riihl, judged by the examples in the 

 British Museum coll., are without blue scaling ; the specimens from 

 the Altai are strongly blue-scaled. In size, there is also great differ- 

 ence, the examples from the high Alps, where the species is almost 

 certainly only single-brooded, being much larger than normal, whilst 

 Nicholson also notes a large example from Bodo, within the Arctic 

 Circle, and specimens from this locality in the British Museum coll. 

 are of good size. The specimens from the Ural, the Altai, etc., are 

 also large. Barrett says that the variability in size in British examples 

 is such that " some specimens are not much more than half the normal 

 dimensions," but we have never seen anything so small as half the 

 normal size, although Esper's figure of the tiny ab. mi nut us. by some 

 considered doubtfully referable to this species, is exceedingly small. 

 Reverdin observes that the largest of 80 examples in his collection 

 measures 25-5mm. from wing-tip to wing-tip (the same example 27mm. 

 from wing-tip to centre of thorax x 2), whilst the smallest measures 

 17mm. from wing-tip to wing-tip (and 18mm. by doubling distance 

 from the centre of the thorax to apex of wing). Blachier says that the 

 normal size of specimens in the Geneva district is about 20mm., 

 but he notes an example (from the Saleve) measuring only 15mm., 

 whilst others from the same locality measure 25mm.-26mm., and 

 yet others from the Alps (of the form alsoides) expanding 26mm.- 

 27mm., Kehfous also notes a specimen from Geneva as small as 15mm. 

 Grund states that, in Croatia, the wing-expanse varies from 19mm.- 

 25mm. Weir records that British examples in his collection varied 

 from 17mm. -22mm., Edgell observes a small one captured in the 



