274 MEMOIRS NATIONAL ACADEMY OF SCIENCES. vol. xii. 



marked with obscure greenish yellow. Anal legs black, inclosing 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 throughout. On the dorsal 

 side it is of a shining bluish white with a yellow tinge. Four black dorsal dots on the prothoracic 

 segment arranged in a square, and two larger black spots in front of each pair of horns; on 

 each abdominal segment three or four minute dorsal black dots. On the side of each segment 

 are seven to eight black spots which are arranged in two rows, one (containing the larger number 

 of spots) straight, including the black spiracles, the other broken up into an oblique row of about 

 three spots on one side of each segment and passing up the front edge of each segment. Farther 

 down on each side is a large black spot over the base of each midabdominal leg. 



The head is striped with black, with five irregular unequal short black lines on each side, 

 while there are two black patches next to the antennas. 



The horns are now long and slender, a little tapering, but blunt at the tips; those of the 

 third a little longer than those of the second thoracic segment, and between a third and a half 

 as long as the body; the caudal horn is about one-fourth as long as the body, while those of 

 the pair on the ninth segment are slightly more than half as long as the caudal one. The horns 

 are all more decidedly curled or twisted than before, and the fine spinules more developed. 



On abdominal segments 1-7, in the place where tubercles should be, is a group of 10 

 minute very short somewhat scattered setse, indicating that they may be the vestigial remains 

 of a tubercle; there are two similar groups on the ninth abdominal segment, of 6 s imil ar fine 

 setse. 



End of the suranal *plate black; the surface smooth, not finely tuberculated. 



Under side of the body pale greenish, with a median interrupted black line, and on each 

 side higher up is a"beavier black stripe, more or less undulating, and on the abdominal leg-bearing 

 segments they are slightly oblique, ascending toward and reaching the front edge of the segment. 



It moulted about May 20-21. 



It is noteworthy that on the front edge of the prothoracic segment there are six vestigial 

 tubercles, indicating the descent of this genus from ancestors with six tubercles. The two 

 dorsal ones form a very small, nearly obsolete, slightly marked transverse rough area; but in 

 front of the spiracle is a large low rough slightly raised round area with very short fine seta?; 

 below, above the base of the legs, is a more prominent brown one. The corresponding ones 

 on the second and third thoracic segments are still less marked, being only faintly visible. 



Stage V: Length 63-76 mm., width of head 6£ mm. The body is now without horns, and is 

 smooth, cylindrical, a little flattened and naked, with minute tubercles in place of the horns. The 

 head is flattened in front, a little angular on the sides; the surface rough and straw-yellow, 

 with five black lines of uneven width and length, a black band ending on the eye area, there 

 being in all eight lines and spots. Clypeus whitish, with two semicircular cross bands. There 

 is a whitish patch in the middle of the vertex, and a whitish area on the sides. 



The body is less cylindrical than in the previous stages, being a little flattened, and has 

 the general appearance of a hornless Sphingid caterpillar. 



The ground color is a delicate greenish pearly or porcelain white, bathed on each side of 

 each segment and along the hinder edge of each segment with pale straw-yellow. On the 

 smooth prothoracic segment are four black dorsal spots, two round ones in front, and two large 

 ones behind; a lateral long stripe behind the spiracle. There are no marked dorsal spots; 

 those of the oblique lines are minute, and the black marks are chiefly confined to the spiracular 

 series. 



On the second thoracic segment in place of the two horns are two low, rather large fleshy 

 tubercles which are a little larger but not so high and prominent as those on the third thoracic 

 segment, though the two latter are less broad at the base. 



