Packard. ] 
534 
[Feb. 19, 
much larger and more imposing than in the earlier stages ; all these 
changes adapting the caterpillar more completely to its exposed 
mode of life. 
The head is now deep coral-red, smooth, with no traces of the tu- 
bercles characteristic of the previous stages, the vertex being smooth 
and simply bilobed. The two prothoracic dorsal spines instead of 
being larger than the other thoracic spines, as in Stage II, are much 
smaller, being only about one-fourth as long or as high as the mes- 
othoracic pair ; the latter are a little thicker, but shorter than those 
on the third thoracic segment. Those on the first abdominal seg- 
ment are very long, rather slender, and arise from a deep coral-red, 
soft swollen hump, whose soft red swollen sides descend so as to 
embrace the spiracle. The dorsal spines of the second abdominal 
segment are of the same size as those on the third thoracic segment, 
those of the following segments decreasing in size to those of the 
seventh segment, while those on the eighth are slightly larger than 
those on the tenth segment. 
The suranal plate is rounded lozenge-shaped, with a row of four 
large piliferous warts extending across the middle, while around the 
hinder edge are four smaller ones. On each side of the black dorsal 
line are seven wavy black lines alternating with white ones, so that 
the caterpillar is very conspicuously banded and spotted. The small 
black tubercles on the side of the body all bear a single hair. The 
anal legs are normal, about a third smaller than the other abdominal 
legs, and with numerous hooks. The end of the body is often up- 
lifted. 
Until we know more of the exact structure and markings of the 
first stage, it would be premature to attempt to fully recapitulate 
the leading points in the ontogeny of this curious larva. 
What we have taken to belong to the second stage of concinna , 
and whose exact coloration we failed to note when collected, shows 
that even probably when hatched from the egg the larva is provid- 
ed with its full complement of spines, and even more, there being two 
on the head, which are lost in the last stage. Without specimens 
of the other species for comparison, we cannot properly interpret 
the nature of the singular ornamentation of this larva, so unlike 
that of any other Notodontian of the American or European fauna. 
To recapitulate, it is to be noticed that : — 
1. The head is deep dull amber in stage II, becoming black in 
stages III and IV, and deep coral-red in the last stage. The head 
