30O LEPIDOPTERA. 



paler behind. • Female similar but darker, and with a black 

 central spot to the hind wings. 



Rather variable in the ground colour, which in the male is 

 often tinged with brown or with slate colour, but in the 

 female varies from light umbreous to smoky-black, in the 

 latter case with all the markings obscured, or with the central 

 shade intensified into a black central transverse bar. In 

 the paler forms a suffusion of smoky-brown or smoky-grey is 

 not unusual, sometimes in the middle of the wing, oftener 

 toward the hind margin. Specimens in the cabinet of the 

 late Mr. F. Bond, obtained from the West of England, are 

 larger than ordinary, with paler colour and less distinct 

 markings — in these respects drawing nearer to the much 

 larger form found on the Continent of Europe. 



On the wing at the end of May and early in June. 



Larva when full grown an inch and a half long ; stout ; 

 blackish-green, showing a double dorsal line enclosing the 

 finest thread of paler ; subdorsal line also paler, slender, 

 edged above with darker green ; below this a broader pale 

 stripe, and another along the spiracles, which are large and 

 black ; raised spots dark brown, larger on the anterior 

 segments, always furnished with a slender hair ; head shining 

 black, mouth greenish ; dorsal plate jet black, finely divided ; 

 under surface paler green. In early youth the larva is green 

 — at first yellowish-green, after the first moult much brighter 

 in colour, but with the usual raised dots black. The mark- 

 ings, as mere pale longitudinal stripes, are very similar 

 throughout. After the third moult the ground colour is 

 pinkish-brown ; after the fourth moult dingy grey-brown ; 

 after the fifth dark slate-grey, tinged with greenish beneath, 

 and it is only after a sixth moult that the adult colouring is 

 assumed. 



End of June to April, on Thymus scriiyllum (wild thyme). 

 The full growth, with the six changes of skin, takes place by 

 the end of September, and the larva, after feeding a little in 



