134 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



type of I. jocOKd. The latter is also more generally subocherous than usnal. and witliout a line on 

 the hind wing. 



For the opportunity of examining five alcoholic exami)les of the first stage of this larva, I am 

 indebted to Professor Riley; those of the last stage I have collected from the poplar. Mr. H. 

 Edwards (Papilio, iii, 24) briefly describes the second stage, and adds that it "feeds in coni])anies 

 until alter the second molt; tlie larva? then separate and act independently of each other."' 



Tlie eggs of the normal form of this species (i. e., I. inrlusa) were received from Jlr. W. N. 

 Tallaut, of Columbus, Ohio. They were laid July 20 and the larva; hatched August 10 or 11. It 

 feeds at first socially on the aspen, eating out patches on the under surface of the leaf. 



Ei/fl. — Diameter about 0.0 mm. Hemispherical, rather high; the shell is thin, white (the egg 

 is reddish just before the larva hatches). The shell under a Tolles half-inch objective is seen to be 

 covered with minute polygonal cells which are tolerably distinct, with slightly thickened walls. 



Larva, Stage I. — (Hatched August 10-11. Descril)ed two days after hatching, and also from 

 alcoholic si)ecimens of the same brood.) Length, o mm. The body is rather long, cylindrical, 

 head rounded, but little wider than the body at first before the latter becomes filled out after 

 eating a few days, as later it is no wider than the body; it is shining jet-black, and provided with 

 scattered, long, stiff, tapering bristles. The prothoracic and suranal plates arc sliiniug brown- 

 blaclc. The former is moderately large, about three times as broad as long, irregularly trapezoidal, 

 narrowing a little behind, and shows no signs of division into two halves; four hairs arise from 

 the front and four from the hinder edge. The piliferous warts on the thoracic as well as 

 abdominal segments are more or less conical, and none bear more than a single hair. The second 

 thoracic segment bears two minute median dorsal tubercles, one on each side of the median line 

 of the body, and smaller than those on the third segment, while the next one on each side of the 

 body is larger than tlie homologous ones on the third thoracic segment. The tubercles on the 

 second and third thoracic; segments are arranged across the segment in a straight line, four of 

 them being visible on each side above. On the abdominal segments the four dorsal tubercles are 

 arranged in a more or less curved line, the curve becoming more marked toward the end of the 

 body, until ou abdominal segment S the curve is almost semicircular. On the first abdonunal 

 segment the two median tubercles are larger than auy on the thoracic segment, and are larger 

 than the subdorsal and lateral ones on the segment in question, and are decidedly larger than the 

 homologous ones on the second to seventh abdominal segments. The four dorsal tubercles on 

 segments 2 to 7 are all of the same size, but the two on the eighth segment are nearly as large as 

 those on the first, and are about twice as large as those on the seventh abdominal segment; on 

 the eighth segment, however, the subdorsal tubercles are nearly as large, but are narrower than 

 the two in the middle. This segment is slightly humped, and bears a brown spot surrounding the 

 bases of the two twin tubercles, and a similar spot occurs on the first abdominal segment. The 

 four dorsal warts on segment 9 are arranged in a trapezoid, the two in front being one-half as 

 large as the two behind. The upper subdorsal row of tubercles are jjartly connected by short 

 lines- or streaks, and between this and the next row of warts lower down is a broken fine brown 

 line, which is, however, almost obsolete. A fine nearly obsolete (or is it incipient?) dorsal browu 

 line. In more advanced specimens the body is ]>lainly striped on each side with three interrupted 

 dark reddish lines. The pilifei'ous tubercles or warts are dark browu, and give rise all over the 

 body to but a single hair. A pair of especially large long hairs arises from the second thoracic and 

 ninth abdominal segments. The hairs are long and slender, and though under a low power they 

 appear to be tapering, under a one fifth objective they are seen to be docked or blunt at the end 

 and some at least slightly but distinctly bulbous at the tip; they are also seen to be hollow and 

 truly glandular; the end ai)pears to be flattened; as seen sideways, the hairs appear to taper. The 

 hairs vary much in length, some being longer th;in the body is thick. An unusual, if not unirpie, 

 feature, exceptional among bombj'cid larv* in the first stage, is the microscopic hirsuties clothing 

 the bodj'. LTnder a one fifth inch objective the microscopic hairs are very short, quite uniform in 

 length, very dense, and taper to a point. 



The suranal jjlate is distinct, blackish, nearly as long as broad, rounded triangular, and bears 

 on the edge eight piliferous warts of ne.arly equal size, besides two arising from the surface, a little 

 in front of the middle. The spiracles are round and remarkably small. 



