1893.] 1^*5 [Packard. 



Stage II. — Described May 13. Length, 4-5 mm. The body still de- 

 cidedly tapers to the end, though now the head is no wider than the body, 

 which is blackish, with a blackish dorsal line not yet turned blue ; the 

 sutures are brownish ; the hairs long and rusty brownish. The pilifer- 

 ous prothoracic tubercles are now small and not conspicuous as they 

 are in Stage III. 



In some observed April 26 (length, 5 ram.), and belonging to an ear- 

 lier brood, the median dorsal black line was broken and on each side of 

 each segment is a black blotch. The dorsal hairs brownish, those on the 

 side gray, and some of those on the back tawny. 



In another set of larvae, from the web on wild cherry, 5-6 mm. long, 

 described May 5, and apparently at end of second stage, the head is not 

 so wide as the body, and considerably narrower than the prothoracic seg- 

 ment. There is no blue about the body. The head and prothoracic seg- 

 ment are black. A distinct black dorsal line interrupted at the sutures. 

 On each side is an obscure similar dark line, but more interrupted and 

 the spaces between tlie sections longer ; below each section on each seg- 

 ment is a large, conspicuous, black, longitudinal, irregular, oval spot, 

 immediately below wliich is a wavy light line, and parallel to this is a 

 similar light line, below which is a fringe of whitish hairs projecting 

 from the body. The dorsal hairs are pale ash-gray, not distinctly tawny. 

 Abdominal segments 8-10 black, without markings. Some of the larvae 

 are much paler than most of the lot examined. 



Stage III. — Length, 7-8, becoming 9-10 mm. Described May 13. The 

 body still tapers to the end. The lateral prothoracic tubercles are well 

 marked, and there is a pair of small dorsal ones on each succeeding seg- 

 ment of the body, bearing the usually tawny hairs, those on the sides being 

 white, with some black hairs. A distinct blue dorsal stripe, beginning on 

 the second thoracic segment and disappearing on the eighth abdominal seg- 

 ment ; it is of the same hue as in the full-fed larva, and bordered with a 

 tine wrinkled white line. There are two lateral white thread-lines, the 

 upper one the more distinct ; towards the end of the stage tliese lines 

 change to a blue. Between these two lines is a row of minute black 

 warts. The larvae when in this stage vary much in the distinctness of 

 the dorsal median blue stripe. It molted May 30-22, the length of the 

 stage being about seven days. 



Stage 1 V. — Length, 13-14 mm. The blue line is as in the full-fed 

 larva, but the lateral, linear, upright blue lines, one on each side of each 

 segment, have now appeared, and also the very irregular, short, thread- 

 like blue and yellow lines on the top and sides of the body. The lateral 

 prothoracic tubercles are still pronounced. It molted June 5-6 ; the 

 duration of the stage being about fourteen days. June 8, 9, 10, full- 

 grown larvae seen out of doors. June 14, they were spinning their 

 cocoons. The season was two weeks late. 



In specimens of this stage, 22 mm. in length (described May 24), the 

 dorsal band is now continuous and firm, not broken, and pale blue. On 



FROG. AMER. PHILOS. SOC. XXXI. 141. X. PRINTED MAY 11, 1893. 



