41 



SUB-GENUS STEYMON. 



Hubner. 

 Females with no velvety patch on the fore-wing. 



THECLA W-ALBUM. 



Black Hair-streak. 



W-ALBUM, Knoch. W-al'bum, on account of the white W on the under- 

 wings. 



This species averages about an inch and a half in the expansion of its 

 wings. 



This is very much like the next in appearance. On the upper side 

 it is a very dark brown, almost black, with an orange spot at the anal 

 angle of the hind-wings, often very indistinct. On the under side it is of 

 an ashy brown, with a row of orange lunules at the hind margins, most 

 distinct at the anal angles. A white hair-like line crosses both wings, and 

 forms a W near the inner margin of each. This last character will at once 

 distinguish it from the next species, Pruni. 



The eggs are laid on the twigs of the elm and wych elm in July and 

 August, and in shape are somewhat like an orange, but are more depressed 

 on the crown ; they are of a whitish colour, and remain firmly glued to the 

 rind of the twigs throughout the winter (Newman.) 



The caterpillar is pale green, with short brownish oblique streaks on the 

 side, sometimes with two rows of red spots down the back, and a dull red 

 stripe on each side above the feet. The head is dark brown and retractile, 

 and the body is covered with soft delicate hair. It feeds on elm, wych elm, 

 and also blackthorn in May and June. 



The chrysalis is short and obese, ferruginous, with three dorsal rows of 

 brown dots. 



An ichneumon fly, viz. Perilitus scutellata had been bred from it. 



The butterfly appears at the end of June or in July, and continues on the 

 wing till August. 



It is found in Central and Southern Europe, and Northern and Western 

 Asia ; but seems to be everywhere confined to very restricted localities, and 

 to be of somewhat uncertain appearance. 



It is unknown in Ireland, Scotland, and the Isle of Man. In England it 

 is widely but not generally distributed, and does not occur north of York- 

 shire ; nor is it found in Wales, or the South-western counties. 



The first to record it as a British species appears to be Lewin, who in his 

 " Insects of Great Britain/' writes thus, " This butterfly is not common. 



