Dec. 1806.] Dyar : Life-Histories of N. Y. Slug Caterpillars. 177 
row dorsal line on the second to eighth plates dark-brown ; hump oppo¬ 
site fifth plate very dark; glandular centers of plates also dark ; a 
white spot in the ridge at the eighth plate (joint 10-11) and a little one 
at the seventh plate best seen from the side. First dorsal plate and all 
the sides dark leaf-green, the glandular centers of the upper plates (7) 
dark. Length 5. 6 to 7. 9 mm. 
Stage VI .—Shape and markings as in the next stage. The last 
four stages are throughout practically alike. Length, 7.3-12 mm. 
Stage VII. —Elliptical, ending in a pointed tail; dorsum slightly 
concave (Plate VII, fig. 6) lowest along a line just above the subdorsal 
ridge where the dorsal and lateral scaling meets, greatly arched; sides 
perpendicular, concave, diminishing at each end and without ridges, 
the whole shape box-like. Setae fine and obscure, a single one on the 
dorsal and lateral aspect of the ridge and a few microscopic ones on the 
sides near the spiracle, the latter secondary. Depressed spaces con¬ 
verted into scarcely sunken angular plates, the dorsal ones (Plate VII, fig. 
7) suggesting the plates, of a tortoise. A row of ten segmentary glands 
on the lower side of the subdorsal ridge secrete an odoriferous fluid when 
the larva is irritated. Plates as described above, the latticed ridges 
scaled, the two directions meeting at the lowest point of the dorsum 
(Plate VII, fig. 11); scales arranged as if overlapping (Plate VII, fig. 12); 
plates irregularly finely granular (Plate VII, fig. 12). Setae weak, 
normal (Plate VII, fig. 5). Opposite the fifth dorsal plate the ridge is 
thrown into a prominence more or less distinct, sometimes also one at 
the sixth plate (Plate VII, fig. 14). These humps are intersegmental, 
representing the incisures of joints 7-8 and 8-9. A white spot on the 
ridge at eighth plate. Color very variable, scarcely two specimens 
alike. Ground color green, more or less replaced on the dorsum by 
brown or yellow or both, variously mottled and spotted, the latticed 
ridges and glandular spots darker usually. Sides less commonly marked 
with brown, but occasionally so and independently of the dorsum. 
The order of appearance of the dark marks is from the hump and white 
spot, spreading on the dorsal area, and from the middle of the 
subventral edge and the white spot, spreading on the lateral area. I 
have not seen either an entirely green or entirely brown specimen. 
Length, 12 to 18 mm. 
Food-plants .—Various shrubs and trees. Oak, chestnut, wild 
cherry, hickory, sweet gum, bayberry, linden, witch hazel and hop horn- 
bean have been noted by me. 
