274 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



markings are obsolete, iuchuliiig the margiiuil dots ou both pairs of wings; as this is from southern 

 Utah, it is much bleached and rather larger than usual; it is aiiotlier 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. 



^,/,/. — Slightly more than heniispherieal, the base flat, color dead black; diameter, 1.2 mm. 

 Of the Californiau form, " color dull, brownish black, smooth. Diameter, about 1 mm. Duration 

 of this stage, eight days." 



Larva. — Messrs. II. Edwards and S. L Elliot (Papilio, iii, 130) liave well described the larva 

 of this species, which lives on 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 the two foregoing species. 



Larva, Stage L. — Var. cinercoides. "Head dark red-brown. (Jn joint '2 are two brown proc- 

 esses, minutely spined. Joint 13 has two " tails " 3 mm. long, brown, twice broadly aunulated with 

 pale yellow and nunutely spined. The body is brown, with three dorsal pale yellow patches; oa 

 joints 2 to 0, 8 to 10, and 12, respectively, the posterior one faint. Venter and legs pale whitish. 

 Length of larva, exclusive of the tails, 1 mm. It spins a slight web on the surface of the leaf to 

 which it clings (p. 82). 



Sf(((/e II. — "Length, without the tilamental legs, 12 mm.; of the latter, 7 mm. It is at once 

 distinguished from the larvic of G. occidentalis and C. boreaUs 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 tlie genus, as are the two lateral prothoracic 

 "horns" and the cervical shield from which they arise. The "horns" are as in C. occidentalis, 

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

 l)atch extends backward 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 species previously described. 



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

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

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

 minute piliferous tubercles on the body; tails spinose, dark red-brown, twice broadly aunulated 

 ■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 Hlled in with purple- 

 brown on joints 2, 3, 6-9, 11 and 13, though not completely on joints 8 and 9, but with a trace 

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



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

 before the apex of each lobe; imrplish black, finely mottled with yellow, green at the sides iioste- 

 riorly; antenme white, ocelli black; width 2.2 mm. Cervical horns thick, covered by piliferous 

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

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

 horns, purplish black, mottled with little yellow spots; a larger patch on joints 1-9, elliptical, 

 retracted at the segmental incisures, reaching the spiracle 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 ou joint 13, replaced by greenish on the anal plate. Tails purjdish 

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



Mature ?«)■)■«.— Length, without the "tails," 38 mm.; of the fllamental legs, 1.5 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 i)rojecting tubercles of the usual 

 size, which are blackish above and pale below. Body pale green. From tlie horns a lilac-red, 

 nearly eqiiilaterally triangular spot edged with yellow, extends backward, its apex resting on the 

 hinder edge of the second thoracic segment. An oval lilac red spot 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 second abdominal segment twice as large as the one in front, succeeded by a much 

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



