104 ILLINOIS BIOLOGICAL MONOGRAPHS [104 



usually but incorrectly listed with Notodontidae. Numerous genera of 

 the family are found in Europe and Asia. 



Head about as high as body, not retractile, about as wide as high ; 

 labral notch deep, either reaching two-thirds distance to clypeus or 

 continued as a groove which reaches clypeus; front extending about 

 one-third the distance to the vertical triangle; head densely covered 

 with secondary setae, thrown back so that the mouth parts are directed 

 almost cephalad. Body cylindrical, covered with numerous secondary 

 setae, some short, others much longer, no fleshy protuberances or ver- 

 rucae present; mediodorsal setae usually grouped into a distinct tuft 

 on each segment, sometimes forming long pencils; setae longer in tho- 

 racic than in abdominal region and on ventral part of abdomen than 

 on dorsal. Prolegs present on segments 3, 4, 5, 6, and 10 as usual, those 

 of the anal segment similar to the others ; crochets biordinal. 



Apatelodes torrefacta has the body densely setiferous, the setae 

 long and soft. Conspicuous pencils are borne on the dorsomeson of 

 the last two thoracic and the eighth abdominal segments. The labrum 

 is emarginate to about two-thirds its depth. A. angelica is more quietly 

 colored, being a grayish brown. The setae of the dorsomeson are com- 

 paratively short, but grouped in a small tuft on each body segment; 

 no pencils are present. The labrum is emarginate about half its depth 

 and the notch is continued to the clypeus in the form of a shallow 

 groove. 



Family Liparidae 



The caterpillars of the tussock moth family may be divided into 

 two groups, those of the first resembling arctians, those of the second 

 having an individuality all their own. Both divisions bear dorsal ever- 

 sible glands on abdominal segments 6 and 7. 



The genera of the first group have t3'pical verrucae, the arrange- 

 ment as in Arctiidae and Acronycta, except that there are three ver- 

 rucae above the Kappa group on the mesothorax and metathorax. The 

 usual variation in regard to kappa on the abdomen is to be observed, 

 tho the fusion with rho in Porthetria dispar is unique. The separation 

 or contiguity of alpha and beta is merely incidental to the amount of 

 development of these verrucae and the area they occupy. 



Group two is a contrast to the commonplace larvae of the first 

 division, being bizarre in color and armature. The long pencils are 

 composed of pecidiar setae with spurs much longer near the tip than 

 at the base. This gives a clavate appearance, altho the seta is not itself 

 swollen. The locations of these "clavate-plumed setae" are good taxo- 

 nomic characters. 



