226 
MEMOIRS OP TUE NATIONAL ACADEMY OE SCIENCES. 
Third stage, — Leiigtli, 12-15 mm. The cliaracters of the iinal stage now appear. The head 
lias changed its shape and style of markings to that of the last stage; it is flatter in front, with, 
a lateral brown line edged with white, while the large, conspicuous, dark spots have flisa])peared, 
and the color of the head is dull opaque-amber. Tlie four reil, parallel, dorsal lines on the second 
and third thoracic and seventh and eighth abdominal segments are now distinct. All the dorsal 
tubercles except those on the iirothoracic and first and eighth abdominal segments have much 
diminished in size, while the others have remained stationary. 
Fourth stage, — Length, 18 mm. The piliferous warts in general are smaller than in Stage 111, 
and those on the prothoracic and first and eighth abdominal segments are smaller than before. 
The eighth abdominal segment is slightly humped, and the anal legs are normal, though about 
one-half as thick as those in front. The body is green, with a broad subdorsal and two narrow 
lateral yellow lines, as in the last stage, the lower being the infra-spiracular line. The sides of the 
three thoracic segments are dotted with reddish pink, and there is a reddish streak on the outside 
of the anal legs. The subdorsal yellow lines diverge on the prothoracic segment, and along the 
next two segments succeeding are edged within with pink red lines. Behind the two dorsal 
tubercles on the first abdominal vSegment they are much farther apart, extending to the supra-anal 
plate, and are whitish yellow, narrowly bordered with deep, straw-yellow, and inclose a narrow, 
yellow dorsal lino. (This line in the next stage extends to the prothoracic segment.) 
Fifth and last stage. — Length, 30-^32 mm. It differs in the dorsal piliferous warts on the first 
thoracic and first and eighth abdominal segments being smaller than in the fourth stage, being 
now no larger than those on the other segments, and the hump on the eighth segment has almost- 
disappeared. There is, as in the fourth stage, a conspicuous red dash on each side of the thu’d 
abdominal segment, and the other lines are as described in the fourth stage. 
RECAPITULATION. 
1. Head largo, with dark spots and connected lines in Stages I and IT. 
2. The spots disappear, and the peculiar lateral dark line edged with white characteristic of 
the final stage appears in Stage III. 
3. The piliferous tubercles on first thoracic and first and eighth abdominal segments attain 
their maximum in Stage II; the tendency after this stage is to return to a simple, smooth body, 
without excessive ornamentation or any decided change in coloration. 
4. In Stage lit all the other tubendes diminish in size. 
5. The style of coloration of Stage V is indicated in Stage II. 
6. In Stage IV the tubercles almost reach their minimum, becoming still smaller in the final 
stage. 
7. The few tenant hairs present in the first stage are battledoor-shaped. 
It is interesting to notice, in reviewing the larval history of this species, the strong tendency 
shown after the second stage to a diminution in size of the tubercles, so that by the fourth stage 
the body becomes smooth and free from all projections, humps, and spines, and thus more 
noctuiform. At the same time the yellow and whitish stripes and pink blotches become indicated 
at an earlier stage tlian usual, as if the aim were to adapt the caterpillar to the ribs and iiarallel 
greenish and yellowish lines or shades of the leaf on wliich it feeds. 
This is perhaps, as regards the other species, the most generalized and simple form in its- 
early larvml stages, there being no horns and the dorsal warts of nearly uniform size. 
In the group comprising JI. biioidata, gutfivitta.f and obllqua there is a singular degree of hyper- 
trophy and specialization of the dorsal tubercles, while in the group represented by 77. 
the process of hypertrophy and specialization takes another direction, i. e., the anal legs, the larvm 
becoming ceriira-form. 
IlKiMARKS. — PI. XXIX, figs. 2, 2a represent what mayi)rove to be the young larva of this spe- 
cies. It was found by Mr. Bridgham on the walnut at Providence, 11. I., July 5. I have no notes 
on it. The following descriptions have been drawn up from Comstock’s specimens, the types of his. 
description in his report as United States Entomologist for 1880. llis Xo. 210, “Xotodonta on 
oak, Sejitember 23, 1870,” is equal to var. c*. of his description. I am indebted to Professor liiley 
