76 PROCEEDINGS OP THE AMERICAN ACADEMY 



had become dark at the tips, but the hairs were still pale. About a 

 day later, i. e. at 5 p. m., the tips of the tubercles only were dark, the 

 bases being still pale yellow as before. 



This stage differs but little from the first, chiefly in the pale honey- 

 yellowish head ; there are as yet no differences in the size of the dorsal 

 tubercles, though they are in this stage pale yellowish at the base, wheie 

 before they were black throughout. 



Stage III. — They moulted again, June 22-23. Length 14-15 mm. 

 The body is of the same yellow hue as before, the tubercles at first 

 being all yellow. The lateral ones are the first to turn dark. The 

 head is pale yellow, concolorous with the body. 



In the preceding stage, on each abdominal segment there is an up- 

 right faint short blackish stripe behind the spiracle ; in the present 

 stage there is a jet-black stripe, which is somewhat curved or exca- 

 vated on the front edge ; there is none on the prothoracic segment, 

 and the stripe is represented on the 2d and 3d thoracic segments by 

 an irregular black rounded dot. At the base of the thoracic legs is a 

 black dot, not present at the base of the abdominal legs. The tuber- 

 cles are nearly of the same shape and relative size as in Stage II., but 

 the six dorsal and four last abdominal (the dorsal ones on 9th and 10th 

 segments) are slightly larger than the other abdominal ones, while the 

 spiracles are larger than before and black ; the other black marks are 

 as before. 



Stage IV. — One moulted again the morning of July 1. Length 

 15-16 mm., one 20 mm. and eventually becoming 25 mm. "When 

 observed an hour or two after casting its skin, the body as before was 

 pale lemon-yellow ; the tubercles of the same color as before, i. e. pale 

 greenish yellow, except those of the lower lateral row which are black 

 on the trunk, but with the head or end and the spines light greenish 

 yellow. The dorsal and two lateral rows of black spots are as before. 

 The head and upper side of the prothoracic segments are shining 

 honey-yellow, as is also the 9th and 10th abdominal segments, ivhile the 

 body is covered with a whitish mealy bloom. 



The larvae, which were reared in Brunswick, Maine, from eggs laid 

 in Brooklyn, seem to feed sparingly and to grow slowly, and were fed 

 at first with ailanthus, and afterwards with wild plum. They became 

 before moulting again very white, the bloom being thick and powdery, so 

 that the honey-yellow head and prothoracic plate, with the suranal plate, 

 together luith the sides of the anal legs and upper part of the 9th ab- 

 dominal segment, contrast with the color of the body. 



In this staofe the two anterior setiferous tubercles on the suranal 

 plate are still well developed, as are also their bristles. 



