Dec. 1896.] Dyar : Life-Histories of N. Y. Slug Caterpillars. 175 
measurements given that they really were stages IV and V. Two of the 
references include a general account of the finer external structure. A 
general and not unnatural error has been made in considering the sunken 
armor plates to represent the segments. Edwards and Elliot say “the seg- 
ments are arranged like the plates of a tortoise,” Dr. Packard refers to 
a marking “along the sutures ... of the segments,” and I have said 
“joints 3 to 13 have each a plate.” These structures are situated be¬ 
tween the segments, overlapping on two adjoining ones. Dr. Packard 
found but seven spiracles ; but he must have had before him an abnor¬ 
mal larva, as all my specimens possess the usual number. 
Description of the Several Stages in Detail. 
Egg, —Elliptical, flat, 1.8 x 1.2 mm., the skin very thin, white and 
iridescent; the fresh egg is transparent with a slight pale yellow tint 
when laid on glass and becoming more opaque as the embryo de¬ 
velops but not darkening in color. Reticulations rounded, obscure, 
rarely angular, not characteristic; the surface of the egg is slightly 
shagreened. Another egg measured 1.7 x 1.4 x.i mm. Laid singly on 
the leaves. 
Stage /.—Elliptical, more pointed behind than before ; dorsum flat, 
a little arched, separated from the perpendicular sides by a ridge bearing 
two rows of tubercles, each with two setae (Plate VII, figs. 1 to 3). These 
represent the usual subdorsal and lateral rows, but situated in close ap¬ 
proximation to each other. On joint 3 four tubercles, on joint 4 > 
three, and on joint 13, three. A subventral row of simple setae. The 
shape is less boat-like than the mature larva, though all the essential 
features are indicated. Pale yellowish, a broad dark band along the 
ridge below the skin and therefore appearing in a slightly different po¬ 
sition according to the point of view. The band is connected with its 
fellow at the ends and also by a bar in the center of the dorsum. Dorsal 
skin smooth, depressed in gentle hollows representing the dorsal (1) 
and addorsal (2) depressed spaces; bases of tubercles wrinkled, sub- 
granular ; lateral (subventral) skin also smooth, with two rows of taint 
depressions. Venter clearer yellow than the body; head pale. Length 
1.2 to 1.9 mm. The larva feeds in this stage. 
Stage //.—Tubercles absent, a single tiny seta represents each. 
Subdorsal ridge rounded, prominent. Dorsum hollowed, sides perpen¬ 
dicular. Skin obscurely granular, the granules flattened, nearly con¬ 
tiguous, not really overlapping but suggesting scales, especially before 
