680 William T. M. Forbes 



mass covered by a sort of varnish. Caterpillar (fig. 431) very hairy, 

 with dense secondary hair on all parts except tips of palpi, even on 

 antennas. (Some primitive forms are like Apatelodes.) Form varying 

 from nearly cylindrical (M. americana) to very much flattened, with 

 lateral lappets on segments (Tolype and Epicnaptera). Notch of labrum 

 not so deep as in Apatelodes. Pupa in a cocoon, which is dense except 

 in M. disstria; more or less densely clothed with secondary hair; palpi 

 well exposed; no cremaster; fore femora covered, and maxillary palpi 

 absent. Epicranial suture distinct. 



Key to the genera 



1. Humeral cell of hind wing about as large as discal (fig. 429). 

 2. Fore wing with all veins preserved; wings very irregular. .. .4. Epicnaptera. 

 2. Fore wing with R„ and R 3 completely united; wings nearly even (fig. 428). 



5. Heteropacha. 

 1. Humeral cell small and inconspicuous. 



2. Outer margin of fore wing distinctly concave at middle; cell of hind wing 



open (fig. 427 ) 3. Malacosoma. 



2. Outer margin of fore wing evenly rounded; cell of hind wing closed. 



3. Thorax with even hair 2. Artace. 



3. Thorax with a strong median crest of metallic scales 1. Tolype. 



1. TOLYPE Walker 



Body very stout and long, with dense woolly vestiture, looser on tegulae; disc 

 of thorax clothed with shining spatulate hairs; end of abdomen with a loose 

 terminal tuft. Fore wing evenly rounded; cell scarcely two-fifths its length; R 4 

 short-stalked. Hind wing rounded, with small humeral cell, and a single long 

 humeral vein, curved out at tip; the other veins arising from the cell. 



Eggs laid in a row, covered with hair from the abdominal tuft. Caterpillar 

 strongly flattened, with lateral lappets, and well-marked subdorsal warts; those 

 on eighth segment of abdomen not enlarged. Cocoon dense, strongly flattened; 

 on bark. Pupa with secondary setae very weak; cremaster indicated by an abrupt 

 narrowing of the end of the last segment. 



Key to the species 



1. Smoky gray, the markings nearly obsolete, except for the pale subterminal 



line 2. laricis J 1 . 



1. Markings sharply defined, in two shades of gray, or in gray and white. 



2. Subterminal band dark gray, contrasting with the whitish base and median 



area ' 2. laricis $. 



2. Median area dark, concolorous with the subterminal band 1. velleda. 



1. T. velleda Stoll. Head and thorax white, abdomen gray, disc of thorax and 

 sometimes base of abdomen contrasting, blackish. Fore wing ash gray, with white 

 veins, and fine, waved, white, ordinary lines, the transverse anterior and trans- 

 verse posterior often double ; terminal line white, followed by gray bars in the 

 fringe. Base, margin, and filling of lines sometimes pale. Hind wing with vague 

 bands. 30-50 mm. (H 11:7 <?, 8 ?.) 



