158 I-IAUSTELLATA. — LIZPIDOPTEKA. 



females : head small, deeply inserted in the thorax, velvety : thorax stout, 

 woolly: wings thick, sometimes subdiaphanous, small in proportion to the 

 bulk of the body ; present in both sexes, with the hinder margin entire : ab- 

 domen robust, slightly tufted at the apex in the males, acute in the females. 

 Larva with ten legs, elongate, cylindrical, tuberculated ; head flat, more or 

 less eraarginated in front: pupa naked, subterraneous. 



Biston was proposed as a genus by Dr. Leach in the Edinburgh 

 Encyclopaedia above twenty years since, his name consequently 

 has the priority of Amphidasis of Treitschke, published within these 

 six years, and improperly retained by Duponchel: — the species are 

 the most robust of the family, and bear considerable resemblance 

 to the Notodontidse, but the different texture of their wings and 

 the structure of the antennse (exclusively of the diversity in the 

 larvae) sufficiently point out their distinctions. Should it eventually 

 appear advisable to break up the genus, the first species ought to 

 bear the name Biston, and the second Amphidasis, 



A. With the antennae, in the males, bipectinated to the apex. 



Sp. 1. prodromaria. Alis albidis, fusco-pulverulentis, anticis fasciis duabus 

 fiexuosis brunneis nigro-terminatis. (Exp. alar. $ 1 unc. 6 — 10 hn. : $ 

 1 unc. 8 lin. — 2 unc. 1 lin.) 



Ph. Ge. prodromaria. Wien. Verz. — Z)ora. vii. joZ. 219. — Bi. prodromaria. Steph. 

 Catal. part ii.p. 117. No. 6454. 



Anterior wings above whitish or cinereous, sometimes flavescent ; delicately 

 sprinkled with fuscous-black, with two transverse flexuous coffee-brown fasciae, 

 ed<^ed on one or both sides with black, one near the base, the other towards 

 the hinder margin ; posterior wings paler or rufescent, dotted with brown, 

 with a single flexuous, more or less evanescent, brown fascia; cilia of all in- 

 terrupted with brown : head and thorax white, the latter dotted with brown : 

 abdomen reddish, dotted with black : antennae black, annulated with white : 

 the radii in the male griseous. Female larger, of a clearer white, with the 

 transverse brown fasciae on the wings more deeply edged with black. 



Very variable : some examples are so thickly irrorated with brown-black as to 

 have the transverse strigse scarcely visible ; and amongst my series, which is 

 very extensive, I possess a specimen entirely of a duU-brown with black dots, 

 and a single angulose transverse black striga on the anterior wings ; others 

 have the posterior fascia extending entirely to the hinder margin ; and one 

 female has the posterior wings totally fuscous. 



Caterpillar variable ; brown or ashy, marbled with yellow or dusky, with white 

 dots and 14 tubercles, the four penultimate of which are largest: it feeds on 

 the oak, lime, birch, poplar, SiC, in June:— tlie imago appears in March or 



