122 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



The subdorsal spines are now miu'li shorter than before and simple and eonieal; while the 

 lateral series, instead of being nearly as lontf as the dorsal ones and deeply forked, are short and 

 stout, ending in three short, stout, piliferous spines. 



The body is now dull chestnut, with dusky diseolorations. but irithmit the decided hhicl' 

 handle and tijxits af st(i<je I. the body being decidedly darker. The black spiracles are surrounded 

 by a difl'use black ring. The thoracic legs are black; the middle abdominal legs jet-black outside, 

 on a chitinized portion; the anal legs are of the color of beeswax, with a jet-black spot or wart 

 at the tip, and a dusky patch on the sides; these Itlack plates are lan/cr mid hmyer than in stage I. 



The descriptions of stages III and IV were drawn up from a series i-eared at my request hj 

 the late Mr. S. Lowell Elliott and preserved in alcohol; the colors are described from a set of 

 drawings by Mr. Bridgham. Mr. Elliott observed five stages. 



Stage III. — (Preserved the third day after the .second molt.) Length, od mm.: width of the 

 head, 3 mm. The head is narrow, about one-half as wide as the second and third thoracic seg- 

 ments; chestnut brown, with two pale, longitudinal bands in front, each band ending at the base 

 of the pale antenna?. TIte two dorsal xpuies on thr jii'othoracic xegiaent are much shorter than in 

 stage II, with much .stouter lateral spinules, and with shorter forks at the tip, and the .spines on 

 the trunk are shorter. The two second thoracic dor,sal spines are a little stouter than before, 

 but are nearly as in stage II. and are spinulated in the same way; thej' are i.o mm. in length; 

 they are pale on the basal half and dark brown on the distal half; the corresponding spines on 

 the third thoracic segment are a little shorter. The dormi and lateral Kpines on (didominal 

 segments 1-7 are much smaller in proportion than in stage II, the dorsal spine being still unevenly 

 forked. The "caudal horn" on the eighth segment is now 3 mm. in length, and is still regularly 

 forked as before. The corresponding single median. spi?ie on the ninth segment is minute and 

 much smaller than hefore. The two larger spines on the suranal plate are smallrr than hefore, 

 each bearing four spines, and behind these on the edge of the plate are four minute conical 

 spines; the plate is regularly rounded behind; it is dark brown in the middle, with paler rounded 

 granulations. On the side of the anal legs is a similarly ornamented distinct, narrou\ triangular 

 field not developed in stage II. The middle abdominal legs are tipped with black as before. The 

 body is more hairy than l)efore. 



The general hue of the body is at lirst pale yellowish brown (raw sienna), with a large pale 

 area around the dark spiracles. There are no distinct markings. Toward the end of the stage 

 the body in those feeding on white pine becomes decidedly reddish, and in fact the color varies 

 from violet through all shades of golden brown and orange purple to black. The horns are ro.sy- 

 red at base; there is a broad, pale, diffuse, subdorsal band on each side and the dark .spiracles are 

 rendered very conspicuous by the broad yellowish ring around them. 



Fig. 3. — Armature of Hades imperial is. Stage I. a, a dorsal prothoracic spine; h, a sub- 

 dorsal prothoracic spine; c, a dorsal spine of the second thoracic segment; d, a dorsal spine of 

 the third thoracic segment; (% the lirst abdominal segment, side view, showing the anterior and 

 posterior black Vjand, and the position of the dorsal, subdorsal, and infraspiracular spines with 

 the spiracle; /", the suranal plate, in part, bearing the anterior .spine, ending in four setiferous 

 tubercles and the two smaller, .simple spines at the end of one side of the plate; g, the "caudal 

 horn"' or medio-dor.sal forked spine of the eighth uromere, seen partly from the side; g' , end of 

 the same, seen from in front, showing the two forks; A, one of the dorsal spines on the ninth 

 uromere. All drawn with the camera to the same scale. 



Fig. If.. — Armature of Eacles imperialis. Stage II. a, end of one of the dorsal jnothoracic 

 "horns;" 5, one of the dorsal second thoracic "horns;" c, the "caudal horn," or medio-dor.sal 

 spine on the eighth uromei'e. Stage III. d. one of the second thoracic " horns;" f', the "caudal 

 horn" or medio-dor.sal spine of the eighth uromere. All drawn with the camera to the same 

 scale. 



Stage TV. — (Four days after the third molt.) Length, 40 nmi.; width of the head, 4.-5 mm. 

 The characters of the full-grown larva are now nearly assumed. The head is, in one specimen, 

 twice banded with pale j'ellowish in front, in another the l)ands are nearlj' obsolete and the head 



