Paeknnl.] ^^^ [March 17, 



nearly as in Stage 11, and are spinulated in the same way ; they are 4.5 

 mm. in length ; Ihey 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 dorsal and lateral spines on abdominal segments 1-7 

 are much smaller in proportion tlian 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 correspond- 

 ing single median sjnne on the ninth segment is minute and much smaller 

 than before. The two larger spines on the suranal plate are smaller than 

 before, 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, narrow, triangular 

 field not developed in Stage II. The middle abdominal legs are tipped 

 with black as before. The body is more hairy than before. 



The general hue of the body is at first pale yellowish brown (raw 

 sienna), with a large pale area around the dark spiracles. There are no 

 distinct markings. Towards the end of the stage the body in those feed- 

 ing 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 rosy-red at base; there is a broad, pale, diffuse, 

 subdorsal band on each side and the dark spiracles are rendered very con- 

 spicuous by the broad yellowish ring around Ihem. 



Fig. 3. — Armature of Eacles imperialis. Stage I. a, a dorsal protho- 

 racic spine ; b, a subdorsal prothoracic spine ; c, a dorsal spine of the second 

 thoracic segment ; d, a dorsal spine of the third thoracic segment ; e, the 

 first abdominal segment, side view, showing the anterior and posterior 

 black band, 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-d(»rs-al forked spine of the eighth uromere, seen partly from the 

 side ; g', end of the same, seen from in front, showing the two forks; h, 

 one of the dorsal spines on the ninth uromere ; all drawn with the camera 

 to the same scale. 



Mg. 4. — Armature of Eacles imperialis. Stage II. a, end of one of the 

 dorsal prothoracic "horns;" b, one of the dorsal second thoracic 

 "horns;" c, the "caudal horn," or medio-dorsal spine on the eighth 

 uromere. Stage III. d, one of the second thoracic "horns;" e, the 

 " caudal horn" or medio-dorsal spine of the eighth uromere. All drawn 

 with the camera to the same scale. 



Stage IV. — (Four days after the third molt.) Length, 40mm.; 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 yellow- 

 ibh in front, in another the bands are nearly obsolete and the head almost 

 entirely dark chestnut. The two dorsal prothoracic tubercles are now 



