Dec. 1896.] Dvar: Life-Histories of N. Y. Slug CATERriLLARS. 181 



Criticism of Previous Descriptions. 



There are no descriptions of the youngest stages of this species. 

 The references given above cover descriptions and figures of the mature 

 larva, many of them inadequate. Walsh describes a larva as tetradac- 

 tylus with but four pairs of long appendages instead of six. I think he 

 had before him a specimen in which the appendages of joint 8 were 

 broken off on both sides, which would leave "the third and sixth 

 pairs" long as he describes, if the missing appendages be not counted. 

 This is very probable, as I often find larvae in various degrees of dilapi- 

 dation. A specimen occurred in which all the appendages were absent 

 except the last two pairs. It was a hardly recognizable object, yet alive 

 and healthy. I have also recorded* an example in which the third ap- 

 pendage (joint 6) was absent on both sides. 



Dr. Packard described a larva as " Fhobetron, sp.," apparently re- 

 garding it as distinct from the common form ; but his brief description 

 contradicts pithecium in nothing. This larva is said to possess some 

 stinging power, but Dr. Packard figures no stinging spines among his 

 excellent plates (Proc. Am. Phil. Soc, xxxi, pi. II and III, figs. 11 and 

 12), and I have been unable to find any such on the larva. 



Description of the Several Stages in Detail. 



Egg. — Flat, circular, not elliptical as usual, scarcely shining, dark 

 ocher yellow, almost brownish; diameter 1.2 to 1.4 mm., height about .1 

 mm. Reticulations rounded hexagonal, regular, very obscure scarcely 

 defined lines resembling the joinings of cells. Laid singly, very rarely 

 two overlapping. The developing embryo finally causes the Qgg to turn 

 dark brown. Hatches in 10 days. 



Stage I. — Rounded elliptical, the spaces proportioned about as in 

 the mature larva, on joints 3 and 4 are three, on joint 5 one, and on 

 joints 6 to 13, two each of long spines, subequal, composed of a taper- 

 ing proximal portion with enlarged base and more slender tapering dis- 

 tal portion (plate, figs, i and 2). Of the subdorsal row, those on joints 

 7, 9 and II lean outwardly, alternating with the others. All have the 

 bases slightly wrinkled. Below the spiracles a series of setae arise from 

 the subventral edge. Color dark brown, darkest along the subdorsal 

 ridges ; a broad whitish dorsal line. Spines white at base, the ends of 

 the proximal part (hypertrophied tubercle) black, the distal part (seta) 

 dusky, both finely spinulose. Head blackish, especially on the vertex. 



When first hatched, the tubercles are small and bear only the dusky 



* Ann. New York Academy of Sciences, VIII, 218, note 2. 



