ME^ilOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 
267 
spotted with still paler x^atches. The prothoracic segment is still large and broad, but the lateral 
X^rojections are much shorter, and now the tubercles of the preceding stages are represented by 
sunken xuts, from the bottom of Arhich arise small hairs.* The hairs on the body are minute, only 
being visible with a lens. The suranal x>late is smooth, the x>apilliforiu tubercles much thicker 
and shorter in xH'ox>ortion than before, and the bristles arising from them slenderer and more 
hexible. The spiuules on the stemapods are much slenderer and smaller than before, but it is to 
be noticed that by this time they are larger on the underside, i. e., that side now almost constantly 
held up and thus more exx>osed to external stimuli, than those on the ni)perside of the filaments. 
The colors of the body are nearly the same as in tStage 11, but the brown is tinged with lilac 
and reddish, with greenish i)atche3 on the upper side of the second to fifth abdominal segments. 
Stage 1 V . — September 10. Length of body, 20 mm. ; of stemapods 15-10 mm. The larva is still 
much x^aler in hue than before, with more decided lilac blotches on the back. The thoracic dorsal 
hiimx) is now very marked, while the lateral [(rejections of the lArothoracic segment have nearly 
disax^peared. The front edge of this segment is vermilion red. 
Full-fed larva. — Length, 45 mm., exclusive of the tails, which are about 15-20 mm. The head 
is i)ale reddish or mahogany -brown ; about one-third as wide as the body at the third thoracic 
segment. The lArothoracic segment is very broad above, square in front on the sides, and not 
ending in a distinct tubercle, but simply a low projection. The body is inile greenish yellow (the 
colors somewhat faded in my three si>ecimens, as t hey are about to transform). A dorsal median 
reddish brown band beginning at each angle of the pi’othoracic segment and narrowing on the 
second and third thoracic segments; it begins to widen on the first abdominal segment, becoming 
widest on the fourth, and extending down on each side to near the base of the abdominal legs, and 
contracting and becoming narrowest on the end of the seventh abdominal segment, and widening 
a little on the ninth. The anal is triangular, rounded at the end; the “ tails” are browui, 
with three pal^^i' rings on the outer half. The thoracic legs are deep red; the abdominal ones 
X^ale, with brown x>lantm. 
It differs from G. mnltiscripfa in that the dorsal reddish x^atch in the middle of the body does 
not descend so far down on the side; otherwise it is like it in general shax)e and api>earance. (Dr. 
Dyar tells me that the dorsal patch is very differently colored in C. mnltiscripfa; it is a wdiite 
X^atch, whereas borealis has a brown one.) 
When at rest the head is retracted and sunken between the lateral fleshy conical luojections 
of the x^i'othoracic segment, Avhich are temxmrarily imx)rovised or ])ushed out by the larva when 
at rest. The thoracic legs are held close to the body and directed forward, the tail extended out 
behind, with the tips slightly curved up, the flagella being retracted. But Avhen irritated or 
teased, and x>i*obably when visited or stung, by an ichneumon, the tails are jerked up and the 
flagella protruded, the head, with the thoracic segment, also bei*ig jerlced u]). The colors at this 
time are [)recisely those of a cherry leaf partly turned yellow and x^ftrtly brown. 
The caterx^illar described below occurred in August and SeiAtember at Brunswick, Me., on the 
asx)en. It axq^arently differs from those of G. occidentalis and cinerea in tlie longer spines on 
the lArothoracic segment in the young larva, and in the smooth slight rounded [(rojections Avliich 
rex)lace them in the full-grown caterpillar. 
Larva hfore last molt . — Length to base of caudal appendages, 11 mm. Head large, full, 
rounded, dark lilac broAvn, si>eckled witli j^ellow, slightly Avider than the body except the front part 
of the prothoracic segment; the latter very broad, over tAvice as broad as long, the front edge 
laterally x>i’odnced, and at each angle bearing a large, long, sxuny tubercle three-fourths as long as 
the segment itself, the tubercle bearing about twelve setiferous siunes; across the x>osferior edge 
of the segment is a roAV of four setiferous si)ines. On the back of the other segments are four 
short tubercles arranged in a short traxiezium, and on each side of the segments are two smaller 
sharp tubei’cles. The dorsal tubercles on the mesothoracic segment are larger than those behind; 
those on the metathoracic segment smaller than those on any other segment. The body tax^ers 
gradually to the end; the sui)raaiial xdate longer than broad, rounded, bearing two long, large, 
^ Lr. Dyar writes lue that he lias never ohserved any species of Cernra to lose the tubercles on tlie cervical horns 
till the last stage. 
