272 MEMOIRS NATIONAL ACADEMY OF SCIENCES. vol. xii, 



Larva. — Stage I: Length 9-12 mm. Width of head \\ mm. Head small, no wider than 

 the body, smooth, jet-black, polished and shining; with scattered long hairs. Body elongated, 

 rather slender compared with Ceratocampid larvae of this slage; the body does not taper behind. 

 On the trunk segments (thoracic and abdominal) are six rows of small black tubercles scarcely 

 higher than they are thick, and giving rise to from seven to eight black hairs about as long as 

 one-third the diameter of the body. The tubercles on the first thoracic segment are no larger 

 than those on the abdominal segments; on this segment they are situated on a black cervical 

 shield, forming a transverse black band, somewhat contracted in the middle. 



Four large, long, thoracic dorsal horns, all of equal length, a pair on the second, and another 

 pair on the third thoracic segment. They are each about one-fifth to one-quarter as long as 

 the body, all of the same shape and thickness, scarcely tapering to the end, which is blunt, 

 black-brownish at the end, flexible, not stiff, rigid and chitinous, and furnished with numerous 

 long fine hairs, which are of nearly equal length; those at the end almost forming a pencil or 

 brush; each hair very finely spinulated. 



The horns themselves are of uniform width, not varying in diameter, and with a twisted 

 appearance, as in stages II to IV. 



A large erect caudal horn on the eighth abdominal segment, a little stouter and not quite 

 so long as the thoracic ones, but like them thin-skinned, hairy, not tuberculated or twisted as 

 in the penultimate stage. 



The dorsal tubercles on the ninth abdominal segments are of the same size and shape as 

 those of segments 1-7. 



Suranal plate small, triangular, black. 



On each side of the base of the plate are two high erect horns, like those on the second and 

 third thoracic segments, but about one-half as long, though of the same shape, thin-skinned, 

 flexible, and with similar black hairs. 



The spiracles are black and inconspicuous. 



Coloration: The body is dull black, except the thoracic segments and end of the body. 

 The thoracic segments are livid yellow, with black patches on the sides; in some individuals 

 the first thoracic segment is black, with a small yellow spot above. There are two dark roundish 

 dorsal spots on the hinder edge of the second and third thoracic segments. Along the body is 

 a faint yellowish spot (sometimes reddish or rusty yellow) on each side above the legs. The 

 eighth and ninth abdominal segments are pale ochreous yellow ; the base of the caudal horn and 

 suranal horns black. 



The distinctive colorational feature is the pale steel-blue ring or band passing around the 

 body in the middle of each segment and the dark sutures, making about 13 bluish ring 

 in all. Of these dark bands, that on the first abdominal segment is the widest, the corresponding 

 ones behind, known by inclosing the spiracles, being a little narrower. The narrow bands are 

 on the sutures between the segments. 



The thoracic and abdominal legs are dark, except the front of the anal legs, which is 

 yellowish. 



In this stage the caterpillar is a very conspicuously marked and colored one, with a formid- 

 able armature in appearance, but the high slender horns are not stiff and spiny, only hairy. 

 It remains to be seen whether this caterpillar is inedible by reason of some poisonous or nauseous 

 secretion. 



The larvae at Providence molted May 8 or 9, having been in stage I about 10 to 11 days. 



Stage II: Length 12-15 mm. Width of head If mm. It does not now much differ in the 

 general proportions and length of the horns from the previous stage, though these are now 

 hairless and twisted and somewhat longer, but the body is now of a porcelain white, and the bands, 

 now brown-blaclc, are broken up into black spots. All the horns are now longer, smooth, without 

 the hairs of stage I, while they appear as if slightly twisted, being enlarged at irregular intervals 

 and there giving off a minute seta. The head is still black; there are two white longitudinal 

 bands, quite irregular in length and width, on each side of the head. The antennas are black 



