574 PROCEEDINGS OF THE AMERICAN ACADEMY. 



out. On the dorsal side it is of a shining bluish white with a yellow 

 tinge. Four black dorsal dots on the j^i'othoracic segment arraoo-ed in a 

 square, and two larger black spots in front of each pair of horns ; ou each 

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

 of each segment are 7-8 black spots winch 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 seg- 

 ment. Further down on each side is a large black spot over the base of 

 each mid-abdominal leg. 



The head is striped with black, with five irregular unequal short black 

 lines on each side, wliile there are two black patches next to the antennae. 



The horns are now long and slender, a little tapering, but blunt at the 

 tips ; those of the 3d a little longer than those of the 2d 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 9th 

 segment are sliglitly 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 often minute very short somewhat scattered setae, indicating 

 that they may be the vestigial remains of a tubercle ; there are two 

 similar groups on the 9th abdominal segment, of six similar fine setae. 



End of the suraual plate black ; the surface smooth, not finely tuber- 

 culated. 



Under side of the body pale greenish, with a median interrupted black 

 line, and on each side higher up is a heavier 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, sliglitly marked transverse rough area ; but in front of 

 the spiracle is a large low rough slightly i-aised round area with veiy 

 short fine setae ; below, above the base of the legs, is a more prominent 

 brown one. The corresponding ones on the 2d and 3d 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 



