29 



natural size crawling on a leaf, and, at the left, one in the curled-up 

 position which it assumes when disturbed. At f 1 it is shown, lateral 

 view, enlarged; the color is light slaty, and the head, it will be seen, 

 is proportionately larger and the legs longer than in its more mature 

 stage; its length is about 2.5 mm . At g of the same figure, the penulti- 

 mate stage, which appears to be the most active, is shown from the 

 side resting quietly on a leaf stalk. 



The full-grown larva. — A mature larva is illustrated at h of figure 8, 

 feeding upon the under surface of an injured violet leaf. It is here 

 represented in its largest state. After ceasing to feed it begins to 

 contract, and assumes more of the appearance of figure 7, £, which 

 represents the larva in its most characteristic form. The general color 

 of the larva, as it approaches maturity, is dark dull olive or slate 

 above with a bluish tinge. It is rather conspicuously marked with 

 minute white tubercular spots, arranged in transverse rows of four 

 dorsal and two lateral on each side, as shown in the illustrations, but 

 these disappear in the contracted final stage and can hardly be detected 

 in preserved specimens. The ventral surface is pale-gray, also with a 

 bluish tinge. 



The length of the mature larva as it lies extended on a leaf just 

 before the last molt previous to the final prepupal stage is about 15 mm . 

 When fully extended it measures 18 mm , and in its contracted state 

 just prior to pupation it is only about 8.5 mm in length. 



A larva that came under observation May 6 will well illustrate the 

 changes of color just prior to and after molting. Immediately before 

 this molt, which occurred at 11.15 a. m., the general color of the dor- 

 sal surface had become very dark, nearly black; a few minutes after 

 molting it was very light, nearly uniform leaden gray, the ventral sur- 

 face but slightly lighter, the head being now light pearl gray, with the 

 black eyes showing prominently. When next seen, about five hours 

 later, the general color had turned to glaucous blue. Next morning, 

 when this larva was again examined, the color had not changed appre- 

 ciably, except that it was a little darker and duller. The color under- 

 goes but little change from this time till the contracted stage is assumed. 



Dr. Dyar's technical description of the mature larva is appended: 



Head rounded, normal, dull black, slightly slaty; eye and mouth black, the 

 sutures around clypeus pale; some short pale hairs; width, 1.4 mm . Body of nearly 

 equal width, slightly largest at anterior end; thoracic feet small, abdominal ones 

 well developed, present on joints 6 to 13 (22 feet). Segments 6-annulate, rather 

 sharply so, and about as distinct as the segmental incisures. Color slaty black dor- 

 sally, not shining, smooth, the dorsal vessel showing darker; below the spiracles 

 olive gray, Thoracic feet pale. On each segment, on second annulet, a transverse 

 row of minute white points, with a second one on first annulet stigmatally; a few less 

 conspicuous ones on subventral ridge. 



Final stage. — Head blackish above, pale below; eye in a black spot; mouth brown; 

 antennae and palpi pointed, minutely brown-ringed; width, 1.4 mm . Body entirely 

 dark olive-gray, rather bluish, slaty, the segments neatly 6-annulate, not shining, 

 evenly minutely granular. Feet transparent, spiracles in paler areas. No white 

 points or tubercles. 



