252 LEPIDOPTERA. 



On the wing from May to August, probably in two 

 generations. 



Larva cylindrical, moderately slender, yellowish white 

 with a reddish internal dorsal vessel ; head bright, light 

 brown; plates both faintly brown, 



October to May in the root-stocks of Achillea millcfolinm, 

 preferring to live gregariously in an old spreading root-stock 

 under the bark of which it burrows. 



Pupa slender, red-brown ; wing and limb-covers rather 

 short, brilliantly glossy ; abdomen more dull, each segment 

 with two ridges placed far apart, the anterior set with stout 

 spines ; cremaster short and blunt, furnished with hooked 

 bristles. In a silken cocoon in the larva burrow. 



The moth is of very local habits ; in its favourite places — 

 often in an old quarry or especially rough hill-side, or railway 

 bank where its food-plant grows in large masses, buzzing 

 about round these masses in the sunshine, or sitting quietly on 

 the yarrow leaves, flying again towards dusk. Found 

 occasionally in the London suburbs; but abundantly in the 

 southern counties from Kent to Devon and Somerset ; and 

 from Essex to Norfolk ; also to Oxfordshire, Bucks, 

 Gloucestershire, and Herefordshire ; more sparingly in 

 Cheshire and Yorkshire, and rarely Durham, In Wales I 

 found it in Pembrokeshire ; in Scotland Mr. Adam Eliot 

 has taken it in Iloxburghshire ; and in Ireland Colonel 

 Partridge has secured it near Enniskillen. Abroad it is 

 generally distributed in Central and Southern Europe ; and 

 in Asia Minor ; and in North America Lord Walsingham 

 found it in Oregon, 



3. D. flavidorsana, Knaggs, alpinana, Wilk. ; quaes, 

 tionana, Zdl. — Expanse I to | inch (12-16 mm.). Fore 

 wings broad, dark brown dusted with yellow, with a broad 

 well-defined orange dorsal blotch, which is not extended. 



