PACKARD. — TRANSFORMATIONS OF SATURNIAN MOTHS. 571 



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 8th 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 9th 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 2d and 3d 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 2d and 3d thoracic segments. 

 Alonff the body is a faint yellowish spot (sometimes reddish or rusty 

 yellow) on each side above the legs. The 8th and 9th abdominal seg- 

 ments 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 thirteen bluish rings in all. Of these dark 

 bands, that on the 1st abdominal segment is the widest, the corresponding 

 ones behind, known by enclosing 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 col- 

 ored one, with a formidable 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 moulted May 8 or 9, having been in Stage I 

 about 10-11 days. 



Stage II. Length 12-15 mm. Width of head 1 i mm. It does not 

 now much differ in tin- general proportions and length of the horns from 

 the previous stage, though these are now hairless and twisted and some- 



