274 MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 



markings are obsolete, iucluiliiig the marginal dots ou both pairs of wings; as this is from soutlierii' 

 Utah, it is much bleached and rather larger than usual; it is another case of the law in the 

 geographical distribution of the moths, that the species become both bleached and larger in 

 , the arid region of the Southwest. 



E(i(j. — Slightly more than hemispherical, the base flat, color dead black; diameter, I.l! mm. 

 Of the Californian form, '-color dull, brownish black, smooth. Diameter, about 1 mm. Duration 

 of this stage, eight days." 



Larva. — Messrs. 11. Edwards and S. L Elliot (L'apilio, iii, loO) liave well described the larva 

 of this species, which lives ou the willow. I have been able to compare some very well-preserved 

 alcoholic specimens of the mature and young caterpillars (kindly loaned by Professor Eiley) with, 

 similar stages of tlie two foregoing species. 



Larva, Stage I. — Var. cinereoides. "Head dark red-brown. On joint 2 are two brown proc- 

 esses, minutely spined. Joint 13 has two " tails ".j mm. long, brown, twice broadly annnlated with 

 pale yellow and nunutely spined. The body is brown, with three dorsal pale yellow [latches; on 

 joints 2 to (J, S to 10, and 12, resj)ectively, the posterior one faint. Venter and legs pale whitish. 

 Length of larva, exclusive of the tails, 4 mm. It spins a slight web on the surface of the leaf to- 

 which it clings (p. 82). 



Stage II. — "Length, without the fllamental legs, 12 mm.; of the latter, 7 mm. It is at once 

 distinguished from the larvje of C. occidentalis and G. IwreaUs of the same size by the larger 

 bristles, the warts bearing them being scarcely larger, but the bristles themselves being two or 

 three times as large. The head is as usual in the genus, as are the two lateral prothoracic 

 "horns" and the cervical shield from which they arise. The "horns" are as in ('. occidental in, 

 being spined in the same manner, and pale yellowish beneath. A large reddish triangular dorsal 

 jjatch extends backwai-d from the horns, the apex resting on the second thoracic segment. The 

 back is discolored from the third thoracic segment to the end of the supraanal plate, not so 

 decidedly reddish as in my specimens of the two other sjiecies previously described. 



Stage HI. — "Head subqnadrate, rounded, flat in front, dead brownish black, the lower part 

 paler and mottled centrally in front with a paler color. Antenna- white, labrum and ocelli brown; 

 width of head, 1.3 mm. Cervical horns thick, heavily spinose, brownish black; several rows of 

 minute ])iliferous tubercles on the body; tails spinose, dark rcdbrown, twice broadly annulated 

 with yellowish and tipped with the same color. Body green, a purple-brown subdorsal line 

 passing down the sides to spiracles on joints 7 and 8, the subdorsal spaces tilled in with purple- 

 brown on joints 2, 3, G-9, 11 and 13, though not completely on joints 8 and 9, but with a trace 

 of a dorsal line on the other joints. A'enter whitish." (Dyar.) 



Stage IV. — "Head higher than wide, rounded, a little flattened in front; a minute tubercle 

 before the apex of each lobe; pur|)lish black, finely mottled with yellow, green at tht^ sides j)oste- 

 riorl}-; antennae white, ocelli black; width 2.2 mm. Cervical horns thick, covered by pilii'erous 

 tubercles with about six rows of similar tubercles on each side of the body, only the upper two- 

 distinct. Color yellowish green. A triangular dorsal patch on joints 2 and 3, covering the cervical 

 horns, purplish black, mottled with little yellow spots; a larger i)atcli on joints 4-9, elliptical, 

 retracted at the segmental incisures, reaching the si)iracle on joint 8, replaced centrally irreg- 

 ularly by yellow and broadly connected with a small patch on joints 10 and 11, widening on joint 

 11 and joining a small patch on joint 13, reidaced by greenish on the anal plate. Tails purplish 

 brown, twice annulated with yellow." (Dyar.) 



Mature larva. — Length, without the "tails," 38 mm.; of the lilamental legs, L") mm. The head 

 is small, being one-half as wide as the body, reddish, but darker on the sides. 



The prothoracic. horns in this stage are reduced to smooth ])rojecting tubercles of the usual 

 size, which are blackish above and pale below. 15ody pale green. From the horns a lilacrcd, 

 nearly efpiilaterally triangular spot edged with yellow, extends backward, its apex resting ou the 

 hinder edge of the second thoracic segment. An oval lilac-red sjiot edged with yellow on the hind 

 edge of the third thoracic segment separated by the suture from a similar spot on the first 

 abdominal segment, but which is three or four times as large. A transversely subelliptical similar 

 spot on the sec(nnl abdominal segment twice as large as the one in front, succeeded by a much 

 wider one on abdominal segments 3 and 4; that on the lifth segment is of the same size as that ou 



