MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 201 



Witbiu the egg- tlie larva lies with the front of the liead next tlie to)) of the donie, so That the 

 jaws are opposite 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 uj), near the suiuniit. 



Fully fed larra.— In Maine, at Brnnswiek, the caterpillar occurred tully ted on tiie heech.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 tlus 

 readily separated from S. ipomew; 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 off 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 segment is both nutaut 

 and slightly retractile, being invaginated when irritated. The larvie also occurred at Providence, 

 E. I., through September on the chestnut. It is also figured in MS. by Major Leconte as living in 

 Georgia. (PI. XXVI, fig. ic-ie.) 



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 labrum is carnecnis. A i)air of minute piliferous 

 tubercles on the back of the third thoracic segment. On the first abdominal is a large, high, fleshy, 

 cylindrical, uutaiit tubercle of the same yellowisii color as the body; it nods back and forth freely 

 as the creature walks; it bears a pair of cylindrical, chitiuous, piliferous tubercles, with bases 

 rather wide apart, and which are reddish black at the base and pale at the tips. On the fifth 

 abdominal segmeut is a large, broad, fleshy hump, concolorous with the body, from which arise 

 two low, conical, nutant, fleshy tubercles, each bearing a low chitiuous piliferous tubercle. (This 

 hump and its tubercles are not developed in S. unicornis.) The eighth abdominal segment is 

 provided with a prominent, narrow, fleshy hump bearing two small piliferous warts. The anal 

 legs are about one-half as thiclc as the middle abdominal legs. 



The body is uniformly the color of pale unburnt or I'hiladelphia brick, or of the same tint as 

 a sere, pale brown leaf, with no green upon it. There is a broad dorsal dark brown stripe along the 

 thoracic segments, which is continued upon the base of the head, which bears a broad triangular 

 dark spot. Uehiud the first abdominal hump is a long triangular flesh-colored dorsal baud; on 

 the third abdominal segmeut is a shorter similar patch, while a similar carueous band on thefourth 

 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 reddish lines. 



The apparent aim, or rather the result of the action of the environment, has been to jtrodnce 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 differeuce iu the slightlj- smaller dorsal tubercles, especially those on the eighth and ninth abdominal 

 segments. There are probably slight differences in color, bnfc Professor Riley's specimens are faded out from long 

 immersion in alcohol, so that it is impossible of course to say how the two larvit differ iu color until the two foruis 

 have been compared in the living state. 



Second stage. — Length, 7 mm. Of the same size as S. ipomew of the same stage. The tubercles do not differ iu 

 shape or in size. The specific difference (besides those of color, about which I can not ascertain) is that the two 

 vertical lobes of the head are more acute than iu .>>. ipomew. while the surface seems to be less distinctly marked. 

 Moreover, the paddle-shaped glandular seta: are decidedly shorter. By these marks alone alcoholic specimens of 

 the larv;e of the two species of the present stage can be easily separated. 



Third staye. — Length, 11 mm. The same differences obtain <as in the preceding stages. The vertical lobes of the 

 head are more acute iu & lepiiiioides than iu S. ijmmea; while the seta;, now less flattened at the end, are in shape 

 like those of the third stage of S. ii)(ime(e, but are decidedly shorter. The dorsal and other tubercles are just as in 

 S. qjomecv. It is probable that other specific distinctions are to be sought for in this style of coloration. Indeed, as 

 may be seen in alcoholic specimens, the head of 5. leptinoides is simply rough on the surface and uniformly resinous, 

 while in S. ijioinea- of this stage the surface iu front and on the sides are divided into whitish areas bounded by 

 brown lines. The coloration iu geueral is much alike in the two species. The dorsal band along the thoracic 

 se ments and the V-shaped whitish yellow mark on the sixth and seventh segmeuts are nearly as in the third stage 

 of jS. ipomem. 



