22 TORTRICINA. 



anterior wings at once separate it from the other species of this 

 genus : some pale instances, however, of A. Betuletana might be 

 mistaken for it; but the posterior margin of the basal cloud in 

 the latter species is undulate in a straight direction, or nearly so, 

 whilst in A. corticana it is concave as well as undulate. 



The imago appears from June to August among birch-trees. 

 It occurs at Coombe, Birch, Darenth, Dulwich, West Wick- 

 ham, and Plumstead Woods, Epping Forest, in Worcestershire, 

 Cheshire, and at Torwood in Stirlingshire, N. B. 



The larva most probably feeds on the Birch (Betula alba), as 

 the perfect insect is always taken where such trees grow. 



2. Betuletana, Haw. Alis anticis niveis, aliquando oehraccis ; 

 basi pone medium nigro, fusco, ochraceo plumbeoque variegatis ; 

 apice cinereo-strigato ; posticis fuscis. tf Exp. al. 9-10 lin. 



Head dull dark brown, pale over eyes. Face same colour as the 

 head. Eyes black. Palpi at the tips, above, between, at sides, and 

 beneath, dull dusky brown, merging into whitish at the base. 

 Antennae dark brown, the basal joint clothed with black scales. 

 Thorax dark brown, alternated with transverse bands of hoary grey ; 

 sometimes these bands have a ferruginous tinge ; the bifid tuft deep 

 ferruginous. Patagia same colours as the thorax. Anterior wings 

 shining snow-white at the apex, with dull, curved, grey streaks, 

 most intense along the apical margin, and usually without black 

 dots. The dark portion of the wing extends two-thirds along the 

 costa, and near to the anal angle, on the dorsal margin ; it is beauti- 

 fully mottled with iron-grey, fuscous-black and white markings, in 

 which may be traced a basal patch much interrupted and broken ; 

 the central fascia is distinctly visible, chiefly of fuscous with black 

 markings bordered with white ; the space between the central and 

 basal fascia filled up with iron-guey ; the costa streaked throughout 

 with grey. On the white part of the wing, near the middle of the 

 central fascia, is frequently a delicate ochreous cloud. Apical scales 

 with white bases and tips, iron-grey in the middle. Cilia pale grey 

 at the apex, darker before, and white at the anal angle. Posterior 

 wings fuscous. Marginal scales fuscous, with luteous bases. Cilia 

 shining, very pale straw-colour. Abdomen pale fuscous, the caudal 

 tuft drab. Exp. al. 9-10| lin. 



A very common insect, and varies considerably in the in- 

 tensity of the colours in the anterior wings. In some instances 

 the base is pale, thus approaching A. corticana ; in others the 

 usually white tips are ochreous, which colour also pervades the 

 whole wing. In this latter form it resembles A. ochroleucana. 

 The typical insect is very like A. Caprceana and A. prcdongana : 

 from the former it is distinguished by the straightiy undulated 



