1(30 ]\[EM011!S OF THE NATIOXAL ACADEMY OF SCIENCES. 



variety is almost obsolete, and tlie blaek Hue is wanting. In Bncklers figures of tlie allied 

 (licid'oidi'S there is only a bump. Judging by the figures, none of tbe British species seem 

 identical with ours. In Duponchel and Gueuee's Iconographie et Histoire Naturelle des Chenilles 

 t. ii, the larva is very well ligurod, but there is no horn, not even a marked lateral black line, aud 

 tlie liump is not particularly well developed. We have not seen other ligures of the European 

 caterpillar. 



Mr. Meske also wrote me in 1877 as follows: 



The imago of Xotodonta rimofia Packard stands very near to tbe European Xotodonta dicia'a Linue, but tbe 

 larvaj of those two species are entirely ditferent. Tbe larva of the former is very slender, light green, aud has a 

 caudal horn like a sphinx larva; it feeds ou ro2>iihis tremuloides. This is the second case in tbe North American 

 fauna wiiere tbe imago stands very near to its allied European form, while tbe larva is entirely difi'ereut. The first 

 case is Acronycta occidentalis as compared with Act onycta xisi Linm'. 



It is well to keep the species thus distinct to emphasize the fact that the full-fed European 

 larva is more like the younger stages, having lagged iu its development behind the American 

 form. 



Egg. — Diameter, 1..3.mm. Low heniispherical, about one-half as high as broad. Under a 

 Tolles triplet the- micropyle iu the center is distinctly seen, and the snow-white shell is distinctly, 

 though very finely, i>itted or graimlated. Under a i inch objective the markings are seen to 

 be very peculiar, the surface not being divided into polygonal areas, but studded with nucroscopic 

 beads, which form near the inicroi^yle at the apex radiating series, and lower down lines of beads 

 more or less parallel with the equatorial diameter. From three to seven eggs are laid on a single 

 leaf. Probably the moth files from one plant to another, laying a few eggs at a time. 



F^'e.shly hatched larva, Stage I. — Described a few hours after hatching, before they began to 

 feed. Length, 3.5-4 mm. Tlie head is rather large, shining black, smooth, and considerably 

 wider than the body; not spherical in shape, but somewhat flattened and subcordate or bilobed, 

 as the occiput is deeply indented. A large, broad, but antero'posteriorly rather short, black, 

 mostly smooth, prothoracic plate, with slight roughnesses near the front edge where the hairs 

 take their origin; the hinder edge slightly indented on the median line. On each side of the 

 plate is a lateral black ])iliferous wart. The second and third thoracic segments each with a pair 

 of couspicuoiis, oval, black, flattened, piliferous warts, and two small, I'OTind ones ou each side, 

 the lower one being about one-half as large as the upper. Abdominal segments 1 to 6 each 

 with four dorsal, piliferoits, flattened black warts, the hinder ones a little farther apart than the 

 anterior ones, but yet close to the latter. On segment 7 the four corresponding warts are 

 arranged in a regular trapezoid, the two anterior ones being much nearer together than the 

 two hinder ones. On the eighth segment is a single central dorsal, black, oval, moderately 

 prominent wart, which is twice as large as the largest ou the ninth segment; it is transverse, 

 bearing a bristle at each end, thus having plainly originated from what was once two separate 

 warts. The latter segment bears four black warts, arranged in a regular trapezoid. The ninth 

 and tenth segments are held up when the larva walks. The anal legs are black and a little 

 smaller and shorter than the middle abdominal legs. The black suranal plate is subtriangular, 

 being obtusely pointed in front; the surface is rough, bearing a rough, low tubercle in fronton 

 which are minute piliierous warts. The body is somewhat flattened, being broader than high, 

 and of a pemiliar, pale glaucous or sea green, the skin being polished like porcelain. 



The hairs under a i inch objective are seen to be slightly bulbous at the tip, and therefore 

 glandular, but under a lower power appear to taper like ordinary setae. In Stage II the hairs 

 are also slightly bulbous, and clear at the tip. 



At the cud of Stage I. — Length, 5-('> m:n. The body is much longer than before, so that the 

 tubercles are farther apart, and now the eighth segment has the dorsal wart surrounded by an 

 amber-yellow spot, rendering it more conspicuous, and also the latei'al concolorous line has 

 appeared; the same tint occurs on the base of the abdominal legs. 



(Specimens described in part from life, August 2.) Length at the end of the stage, just before 

 exuviation, G mm. The head is moderately large, in the single larva observed not so wide as the 

 body, as it was about to molt, the prothoracic segment being greatly swollen. (In alcoholic 

 specimens tlie head and black piliferous tubercles of the larva in the nest stage can be seen 

 through.) The head is now black aud slightly bilobed, and 1.5 mm. wide. 



