414 



li represents the European A. betuiaria, bul is much more densely 

 speckled. 



Larva. — I have raised il at Brunswick, Me, from the Missouri currant. 

 According to my recollections, il is a large t hick worm, with a few small t uber- 

 cles, the head notched, the body of the same thickness throughout, and dark 

 brown. The pupa is brown, of the usual shape, and is subterranean. 



PISTON Leach. 



Biston Leach, Edin. Encycl., ix, KM. 1815." 

 Lyeia Hubn. (iu part), Verz., 319, 1818. 

 Amphidasis Treits. (in part), Scbirj. Eur., vi (•)> 229, 1S-.J7. 



Dup. (iu part), Lep. France, vii (iv), 268, 1&29. 

 Biston 6teph. (in part), Nomencl. Br. Ins., 43. 1829. 

 Amphidasis Boisd., Gen. [nd., 195, 1840, 



H.-Sch., Schm. Eur., iii, 99, 1847. 

 Biston Steph. (in part). Cat. Br. Lep., 163, 1850. 



Lederer (in part), Verb. Bot. Zool. Go. Wien, IT?. 1853. 



Guen.,Phal.. i, 204, 1857. 



Walk., List Lep. Het. Br, Mua., xxi, 303, 1860. . 



The species of Biston are distinguished from those of Amphidasis by 



the smaller, more sunken head, the more hairy spherical thorax, and the 

 rather smaller, shorter abdomen. The fore wings have the costa straight, not; 

 curved toward the apex, which is subrectangular, while the outer edge is much 

 less oblique, and is a good deal shorter than the inner edge of the wing The 

 hind wings are a little larger proportionally than in Amphidasis. Iu colora- 

 tion, the species of Biston differ from those of Amphidasis in the three dark 

 lines on the fore wings being subparallel, the outer one not being bent. 



Larva. — " Caterpillars cylindrical, smooth, without other eminences than 

 the trapezoidal ones which form two small isolated points on the 11th ring; 

 head globular; living on trees. Chrysalides quite short, subterranean." — 

 Guene'e. 



Biston ursaria Walker. Plate 11, tig. 7. 



Biston ursaria Walk., Can. Nat. anil Gcol., v, '2(11, 1860; List Lep. Hit. Br. Mux., xxi. 305, I860. 



2 <* audi ?. — Body and wings dark granite-gray. Antennae black, in the 



male heavily pectinated. Palpi blackish. Body concolorous with the' wings; 

 the thorax is a little darker than the abdomen, with two transverse dark lines 

 and a v-shaped line behind. Fore wings uniformly dark granite-gray, darker 

 and more densely speckled than in B. hirtarius of Europe, with three trans- 

 verse, obscure, dusky lines, as in hirtarius, represented by black spots on the 



