PACKARD. — TRANSFORMATIONS OF SATURNIAN MOTHS. 573 



Piothoracic seguieut with only two dorsal spots instead of the four 

 black spots of Stage II, the two dorsal ones conspicuous and elongated, 

 dive rgi nil from each other. 



The 2d and 3d thoracic and 8th abdominal segments, and the suranal 

 plate at the base of the two horns, are now distinctly enlarged or swollen, 

 remaining so through Stage IV, when they are more conspicuously in- 

 flated, much as in Arsenura xanthopus as figured by Peters. All the 

 horns are much as in Stage II, being swollen where a seta is given off, 

 and more or less crumpled, kinky, or twisted. Length of thoracic horns 

 10 mm., being fully one-half as long as the entire body ; length of caudal 

 horn 6 mm. ; of the two suranal horns 3^ mm. 



The black patches more numerous and smaller ; those on the tergum 

 are now broken up into separate spots. There are now on each abdom- 

 inal segment 1-7 three rows of lateral black spots, and a conical one 

 just behind the middle of each segment, or seventeen spots on each seg- 

 ment. Of these three rows the lowest one is the spiracular one, the 

 black spiracle being situated in the centre of the middle one of the three 

 spots forming the line. 



On the 8th abdominal segment are four black spots on each side, one 

 enclosing the spiracle, and a median one behind the caudal horn. On 

 the 9th segment are six black spots on each side and one in the middle, 

 or thirteen in all. Ou the front edge of the 2d and 3d thoracic segments 

 are two black spots. 



The suranal plate is smooth, white, unarmed, no setae, only the two 

 black horns ; the end of the plate is black. 



There is a group of about a dozen minute short fine setae on each side 

 of the tergum of abdominal segments 1-7, marking the probable site of 

 tubercles in the ancestors of the group. 



Above each mid-abdominal leg is a black spot, while the legs them- 

 selves are blackish at base and near the plauta, the basal spot enclosing 

 a white patch ; the hinder part of the leg is marked with obscure greenish 

 yellow. Anal legs black, enclosing three unequal vertical white stripes. 

 Thoracic legs black. 



Under side of the body livid pale, with a wide black lateral and a 

 black middle line. 



This description will almost equally well apply to Stage IV, the two 

 stages being much alike in coloration and armature. 



Stage IV. Described May 16. The length of this stage was 4-5 

 days. Length 42 mm.; width of head 2f mm. 



The body is now still long and slender, and of the same width through- 



