256 LEPIDOPTERA. 



imperceptible shades of colour, from tlie palest whitish brown 

 to fulvous, paler or darker tawny, orange-brown, and even 

 olive-tawny ; usually with a round black spot or dot, in a pale 

 ring, near the apex of the fore wings, and a row of similar 

 spots before the hind margin of the hind wings. Cilia whitish, 

 generally mixed with brown, or with a brown line round the 

 extreme margin. Female similar. 



Under side of fore wings like the upper, but with a 

 perpendicular white bar beyond the middle, and the sub- 

 apical black spot usually larger, distinctly pale-ringed, and 

 often white centred ; of hind wings dark brown, abundantly 

 dusted with hoary, greenish-grey or reddish, with an irre- 

 gular, white, broken, transverse, central stripe, and usually 

 a row of ocellated and ringed black spots before the hind 

 margin. 



Extremely variable, the variations being in the nature of 

 local forms or races, in some cases so well marked and so 

 constant as to suggest distinct species. Haworth described 

 three of the forms found in the north of England as species, 

 under the names of Davus, Typhon, and Polydama, and the 

 opinion of the distinctness of the pale forms with greenish 

 underside from the dark forms with reddish underside, was 

 long held and eagerly defended, and probably is not yet 

 entirely given up. Indeed it would be difficult to believe 

 otherwise, but for the fact that every possible shade of varia- 

 tion is found between them, while no distinction in shape or 

 structure exists. The palest forms (vars. Bavus, F. and 

 Laidion, Bkh.), which are of a yellowish drab or yellowish 

 fulvous colour, are found on mountain heaths, especially in 

 Scotland. In these, the sub-apical black spot of the fore 

 wings is usually indistinct and frequently absent, though on 

 the under side it is nearly always perceptible. The spots 

 forming the row near the hind margin of the hind wings are 

 similarly faint or wanting, and less in number on the under 

 side, though one, at least, is usually visible. In these the 

 dark portion of the underside of the hind wings is of some 



i 



