134 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Stage III. — Length, 30-35 mm. ]\Iolted on the morning (9 a. ni.) of October 10. "When 

 first seen the color of the body was uniformly ])urplish flesh color, with Ijluck markings. The 

 head (width, -i mm.) is dark chestnut brown, with the clypeus and adjoining parts pale. It differs 

 froin the preceding stage in the coni^idcrahly short'/' ulidmninal spinas, while their spimdes are 

 soiiicirhat larger in projiortion than in the jjreviinis stage. The thoracic spines are about or a 

 little more than twice as long as the body is thick, and the abdominal spines are about one-third 

 as long as the bod}- is tliick. The lateral oblique fleshy fold on the abdominal segments have a 

 more distinct dark dash above than in the preceding stage. The legs are black. The caudal 

 spine is now about one-third as long as the larger thoracic ones, lieing in the former stage about, 

 not quite, one-half as long as the longer thoracic spines. PI. LIV, flgs. 2, 3. 



By 2 p. m., October 10. the thoracic and caudal spines, at first pale flesh color, became black, 

 and the head and thorax, as well as the botiy generally, had turned darker. 



It assumes, like I^. iviperialis and A. l/icolor, a Sphinx-like attitude, so that this feature is 

 possibly inherited by the Sphingidiv from the Ceratocanipida' or a similar gi'oup. The thoracic 

 and caudal spines are somewhat sensitive to touch by an intruder. 



Zast stage. — I will first describe an alcoholic specimen, 45-5U nmi. in length, which at first I 

 thought must belong to a fourth stage, or at least one before the last, but, as the head is of 

 nearly tiie same size as full-grown specimens, I am inclined to regard it as simply a belated 

 individual, or one which had recently molted, and had not fed up so as to fill out to its full size. 



Length of body, 45-50 nmi.; lireadth of the head, 6.5 mm. The head is yellowish brown, 

 witli a dark spot on each side of the head opposite the apex of the clypeus. The two dorsal 

 prothoracic spines are nearly as long as the head is wide, but without the long slender spinules 

 of the jjrevious stage; they are yellowish, but black on the distal third; the third or metathoracic 

 pair are a third longer than the body is thick, and, like the others, with short, stout spinules. 

 The abdominal spines are now nuuh shorter than before, with short spinules, though slightly 

 longer than in tlie fully grown examples. The "caudal spine"' on the eighth abdominal segment 

 is as in the full-sized specimens. The general hue of the body is as in the full-grown larva, but 

 the thoracic dorsal black spots are smaller, though the metathoracic segment in front of the horns 

 is deeply stained with black. 



Full-groirn larr<i. — Length, 125 mm.; thickness of the body, 20 nun.; width of iiead, 7 nun. 

 The head is about one-tliird as wide as the body, rounded, smooth, free fi'om hairs, and yellowish, 

 not spotted on the sides, and not lianded as in Eachs imperial is. The body is cylindrical; the 

 skin smooth and shining, not granulated, as in Adelocephala and Eacles. The two middle 

 prothoracic spines are large and long, being nearlj' as long as the head is wide, but the spiiuiles, 

 like those of the other "horns." are now short, thick, and acute, not long and slender as in the 

 previous stages; length, nun.; they are yellowish and black on the outer third. This and each 

 segment of the body succeeding have six well-developed spines, except the eighth and ninth 

 al)doniinal. which have each an additional spine, the large median one. The two lai-ge median 

 horns on tlie two hinder thoracic segments are each about 20 mm. in length; the horns of the 

 second cow corresponding to the subdorsal or supraspiracular row of the abdominal segments, 

 l)eing about half as long (10 mm.) as the dorsal ones; they are also j-ellowish and blackish on the 

 outer third. All tlie six alxlominal spines of segments 1-7 are now very small, slender, and only 

 about twice as long as the large dorsal horns are thick at the base, viz, 4 mm. in length. Unlike 

 the full-grown Eacles. the supra- and infraspiracular spines are as well developed as tiie dorsal 

 ones. On the eighth and nintli abdominal segments the "caudal horns'" are supplemented by 

 two small, slender spines (//), situated just behind the large median horn. Length of the " caudal 

 hoi-n" on the eighth segment. mm., that on the ninth segment being one-half as long. The 

 suranal plate is triangular, the surface rough, with two small tubercles on each side, but no 

 spines. The anal legs are very large, subtriangular. with the outer surface rough, and on the 

 lower edge above the planta is a group of seven or eight minute spines; a similar group of 

 minute spines occurs near the end of the middle abdominal legs. 



For the colors the reader is referred to the hand colored ])hotographs reproduced in Pis. 

 XXI-XXIII of the living caterpillar. We have not yet seen a full-gi-own living larva. The 



