MEMOIRS OF THE oSATIOl^AL ACADEMY OF SCIENCES. 
201 
Witbiii the egg the larva lies with the front of the head next the top of the dome, so that the 
jaws are opi^osite the upper side, hence when it eats its way out of the shell, the more or less 
bean-shaped opening is on one side rather high up, near the summit. 
Fully fed larva , — In Maine, at Brunswick, the caterpillar occurred fully fed on the beech and 
also on the hornbeam during the first week in September. 
This species is of the color of a dry, sere leaf, with no green upon the body, and is thus 
readily separated from 8. ipomece; besides the body is thicker; it bears a striking resemblance to 
a part of a dead leaf, and several leaves were noticed with portions partly cut olf and somewhat 
curled up, to which the caterpillars bore a striking resemblance, both in shape and color. 
It was observed that the high dorsal tubercle on the first abdominal vsegment is both nutant 
and slightly retractile, being iuvaginated when irritated. The larvte also occurred at Providence, 
R. I., through September on the chestnut. It is also figured in MS. by Major Leconte as living in 
Georgia. ( PI. XXVI, fig. 4c-4c.) 
Length, 25-30 mm. The body is compressed as usual. The head is somewhat notched above, 
large and high, compressed, clay-yellow, with two broad dark bands in front, which are made up 
of irregular, wavy, dark lines and spots. The labriim is canieous. A ])air of minute piliferous 
tubercles on the back of the third thoracic segment. On the first abdominal is a large, high, fieshy, 
cylindrical, nutant tubercle of the same yellowisix color as the body; it nods back and forth freely 
as the creatme walks; it bears a pair of cylindrical, chitinous, piliferous tubercles, with bases 
rather wide apart, and which are reddish black at the base and pale at the tips. On the fifth 
abdominal segment is a large, broad, fieshy hump, concolorous with the body, from which arise 
two low, conical, nutant, fieshy tubercles, each hearing a low chitinous piliferous tubercle. (This 
hump and its tubercles are not developed in 8. unicornis,) The eighth abdominal segment is 
provided with a prominent, narrow, fieshy hump bearing two small piliferous warts. The anal 
legs are about one-half as thick as the middle abdominal legs. 
The body is uniformly the color of pale nnburnt or Philadelphia brick, or of the same tint as 
a sere, pale brown leaf, with no green upon it. There is a broad dorsal dark browu stripe along the 
thoracic segments, which is continued upon the base of the head, which bears a broad triangular 
dark spot. Behiud the first abdominal h amp is a long triangular llesh-colored dorsal band; on 
the third abdominal segment is a shorter similar i)atch, while a similar canieous baud on the fourth 
segment breaks up into three diverging stripes ending at the suture. The V-shaped dorsal spot 
on the sixth and seventh segments is faded, pink edged with clay -yellow, and dark brown. Along 
the abdominal segments is a narrow, dark, supraspiracular line. The thoracic and abdominal legs 
are, like the body, pale, with reddisli lines. 
The apparent aim, or rather the result of the action of the euviroiimeut, has been to produce a 
caterpillar whose shape and color represent a sere-brown, more or less twisted portion of a serrated 
leaf, such as that of a beech, hornbeam, and similar trees. 
perceive a dillereiicc iu the slightly smaller dorsal tubercles, especially those on the eighth aud ninth abdominal 
segments. There are probably slight ditterences in color, but Professor Riley's specimens are faded out from long 
immersion iu alcobol, so that it is impossible of course to say bow the two larvaj dilfer in color until the two forms 
have been compared iu the living state. 
Second stage, — Length, 7 nun. Of the same size as S. ipomcw of the same stage. The tubercles do not difier iu 
shape or iu size. The specific difference (besides those of color, about which I can not ascertain) is that the two 
vertical lobes of the bead are more acute thau in S. Ipomciw while the surface seems to be less distinctl}^ marked. 
Moreover, the paddle-shaped glandular setie are decidedly shorter. By these marks alone alcoholic specimens of 
the larvie of the two species of the present stage can bo easily separated. 
Third stage. — Length, 11 mm. The same differences obtain as in the preceding stages. The vertical lobes of the 
head arc more acute iu S. leptinoxdes thau in S. ipomeiVf while the setie, now less llatteiied at the end, axe iu shape 
like those of the third stage of S. iponiea;, but are decidedly shorter. The dorsal and other tubercles are just as iu 
S, ipoxnciv. It 18 probable that other specific distinctions are to be sought for iu this style of coloration. Indeed, as 
may be seen in alcoholic specimens, the bead of S. leptinoides is simply r<mg)i on the surface and uniformly resinous, 
while iu S. ipometeoi tliis stage the surface in front and on the sides aro divi(le<l into whitish areas bounded by 
brown lines. The coloration iu general is much alike iu tlie two species. The dorsal band along the thoracic 
se ments and the V-sbaped whitish yellow mark on the sixth and seventh segments are nearly as in the third stage 
of S. ijxomew. 
