252 



segments. The dorsal bristles of the second and third seg- 

 ments are slightly dusky towards the tip. The remaining 

 seo-ments each have twelve tubercles, disposed in two ranges on 

 each segment, the tubercles alternating on the anterior and 

 posterior portions of the segment, as in E. egle, the two dorsal 

 tubercles of the anterior range being nearer the median line 

 than are the corresponding ones of the posterior range. Most 

 of the dorsal tubercles are of the color of the body, the others 

 are black. These tubercles bear dense tufts of evenly cut 

 bristles, the dorsal tufts of the last segment being a little longer. 

 Length of larva when at rest 16 mm., including the long 

 bristles which extend beyond the head, 19 mm. ; length when 

 in motion 22 mm., the body then tapering towards the head. 



Feeds on Asclepias cornuti; described July 19th, 1875. 

 The larva gradually cast its bristles, beginning with the an- 

 terior segments, and became a pupa on the 23d of July ; the 

 imago appeared on the afternoon of August 3d. Another 

 larva, agreeing with the description, was found feeding on 

 Asclepias verticillata, in 1876. 



From the above description this larva will be seen to be very 

 different from the mature larva of U. egle, as described by 

 Harris (Ins. Inj. Veg.,p. 359) and by Lintner (Ent. Contr., ii, 

 p. 136), but in its uniform coloration to resemble the young 

 larva of E. egle as described by Lintner (1. c). The color of 

 the bristles, however, is neither " white," as in the young 

 larva of both species, nor " slate color," as in Mr. Van Wag- 

 enen's specimens. 



Pupa-shell. Rufo-piceous ; head, thorax and appendages, 

 ninth segment and tip of abdomen, free from punctures. Meta- 

 thorax and first segment of abdomen roughened and having a 

 few punctures intermixed. The segments of the abdomen, 

 from the second to the eighth, distinctly punctured, the mar- 

 gins smooth. Spiracles of the first segment of the abdomen 

 hidden by the wings, the spiracles on the eighth segment im- 

 perfect. The wing-covers reach nearly to the tip of the fourth 

 seoment of the abdomen. The fifth and sixth segments have a 

 pair of slight tubercles beneath. The eighth ventral segment 

 has a slight groove in the median line beneath, and the tip has 



