NORTH AMERICAN LEPIDOPTERA. 127 



tlie S and somewhat thickened. Thorax well developed, rather 

 bi'oader than long, w'ith a transverse ridge of short truncated tuft- 

 ings along base. Abdomen somewhat depressed beneath, with a 

 pointed anal tuft, above which is a larger, but shorter truncated tuft ; 

 laterally with truncated tufts becoming larger toward the tip. The 

 segments are not spinulate, but the posterior edges are somewhat 

 raised and the edge is very densely set with very fine, sharp denti- 

 cles. Legs unarmed, the posterior pair not much longer than the 

 anterior, but apparently much stouter from the dense clothing of 

 long hair on tibi?e ; median tibia with a pair of short terminal spurs; 

 posteriors with two pairs of longer unequal spurs. Primaries long 

 and narrow, very small in proportion to the large body, produced at 

 apex, middle of outer margin and anal angle, excavate between ; 

 11 or 12 veined, venation of the ordinary type. In the % provided 

 on costa beneath, with a loop ft)r the frenelum ; in the 9 this is 

 wanting. Secondaries with 3 and 4 from the end of median vein ; 

 5 nearly midway between 4 and 6 ; 6 and 7 from the end of the sub- 

 costal. In form they are somewhat trigonate, the anal angle some- 

 what produced. 



The side piece of the % is somewhat curved, subequal, obtusely 

 rounded at tip ; inferiorly with a moderate, somewhat curved, pointed, 

 corneous clasper. The supra-anal plate is produced into a rather 

 long, scarcely curved, somewhat flattened, pointed hook ; the infe- 

 rior process is much stouter, about half as long as the superior and 

 also pointed, but obtuse at tip. 



This remarkable genus contains but a single species very readily 

 recognized by the generic characters alone. It is : 



T. abbotii Swains., Zool. 111. i, p). 60, Thyreus ; Harr.,* Sill. Journ. 36, 307, 

 Thyreus; Kirtland, Proc. Ac. N. Sci. Phil. 1837, 148; Wlk., C. B. M. Lep. 

 Het. viii, 99, Thyreus; Clem.,* Journ. Acad. Nat. Sci. Phil, iv, 135, Thyreus ; 

 Morris,* Syn. Lep. 1862, 156; Eiley,* Am. Eut. ii, 123, fig. 84; 2d Eep. Ins. 

 Mo. 78, fig. 54, Thyreus ; Bd., Lep. Gnat. 1870, 66, Brachynota ; Sp. Gen. Lep. 

 Het. 1, 301, Thyreus; Whitney,* Can. Ent. viii, 75; Andrews,* Can. Ent. viii, 

 100; Harris,* Ent. Corr. 284, pi. 3, fig. 9; Saund.,* Can. Ent. x, 130, fig. 7, 

 Thyreus; id. xiii, 2, fig. 2, Thyreus; But!., Tr. Zool. Soc. Lond. ix, .534, Thy- 

 reus; Fernald,* Sphingidse, 22, pi. iv, fig. 4, Thyreus; Grote, Hawk Moths 

 28, Thyreus. 



Head, palpi and thorax dull chocolate brown; hind edge of collar usually 

 black ; a transverse black baud from base of primaries, arcuated cephalad ; the 

 transverse tuftiugs at base, are darker tipped. Abdomen dull brown, blackish at 

 base, somewhat paler and with a more or less distinct iridescence across the mid- 

 dle, darker at tip. The anal tuft is dull yellowish brown, the central pointed 



