70 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Stage IV. — It is possible that the hirva described bj' me in the Proceedings of the American 

 Philosophical Society were small or freshly molted specimens, since an alcoholic specimen 

 represented l)y fig. 2, 20 mm. in length, and in which the dorsal abdominal spines are small, not 

 being difl'erentiated as in the last stage, evidently is in the stage before the last. In this stage, 

 also, the two dorsal spines on the first abdominal segment are simpler and a little smaller than 

 those on the sncceeding segment. 



I therefore cop3' Doctor Jewett's description of this stage, which gives the markings and 

 colors: 



''Larva? passed their third molt June 13. three-fourths to seven-eighths of an inch long, 

 nearl}' cj'lindrical, green. Head green, bilobed, minutely pubescent. Mandibles brown, covered 

 with minute hairs. First segment at first as in last molt, but toward the end of this molt it 

 becomes very prominent and subtriangular in shape, with a yellowish-white line on each side of 

 anterior border, running from near the dorsal to the stigmatal line. The protuberances on the 

 second and third segments have now lost the knobs at their extremities and are brown in some 

 larva? and green in others. The only other changes are that the horn-shaped tuliercles on the 

 fifth to tenth segments are now larger and more prolonged, and are pink on the inside and have 

 the appearance of burnished silver e.xternally, and the stigmatal line is occupied by a marked 

 band of color, consisting of a dark carmine line (passing through the inconspicuous green stig- 

 mata), bordered above by a narrow pale blue and below by a white line. The legs of some larvse 

 are green and of others brown. Prolegs of some, green, and in others green tipped with brown. 

 In some larvte the stigmatal space has numerous small black tubercles on each segment; in 

 others there are no black tubercles." 



Stage F(figs. 3, 3</). — Not seen to molt, ))ut it probably occurred August 1 or 2. Length, 

 25-28 mm. The head is. as before, with two yellow sti'ipes. one on each side, and bordered more 

 or less on each side, especiall}' in front, with black. The four pairs of thoracic horns are now 

 but little longer than the body is thick and are reddish flesh-color, dark at the slender, slightly 

 forked tips, and yellowish griHMi at the base." The '"caudal horn" is now considerably shorter 

 in proportion than before, being about two-thirds as long as the body is thick, and is of the same 

 peculiar deep flesh-red as th« thoi'acic horns. The sharp, stout, spine-like tubercles on the fourth 

 and sixth abdominal segments are slightly over twice as large and thick as the other dorsal 

 tubercles, which are as in the previous stage, and bear a verticil of from three to five short, blunt 

 spinules; they are now silvery white on the outside (Jewett says burnished silver). The lateral 

 yellow, carmine, white and blue })ands ai'e nmch as before. The increase in size of this stage 

 over the preceding one is noticeable. 



In his account of this stage Jewett states that the head is "green, bilobed, minutelj' 

 pubescent,"' also that the tiioracic horns had lost their knobs at their extremities; but this takes 

 place at the time of the second molt. 



In a larva 20 mm. long, and proba))ly of stage IV, the lateral band is tricolored, marked 

 with straw-3'eilow, the yellow inclosing the base of the black spines. Jewett savs: "The legs of 

 some larva' are green and of others brown. Prolegs of some green and in otiiers green tipped 

 with brown. In some larva? the stigmatal space has numerous small, black tubercles on each 

 segment; in others there are no l)lark tubercles." 



The following description of another larva, drawn up Octolier lU and in tiie last stage, ma^- 

 be useful: 



I'l. XLVI, fig. 3. — Length, 24 mm. Body rather thick. Head remarkably Sphinx or 

 Smerintluis-like. as wide as the Ijody, flattened in front, broad below al>out the mouth, but nar- 

 rowing toward tlie \ertex, as in Sphinx; the skin rough; with two lateral, rather broad, yellow 

 lines, which ai'ise from the base of the antenna^ and converging nearly meet on the vertex; 

 "across the upper division of the clypeus is a lilackish band which adjoins a l>lack blotch on each 

 side, and which touches the yellow line. Labrum^pale yellowish, blackish in the middle; eye- 

 patch and mandibles black. 



"Jewett says the spines are "brown in some larvfe and green in others." 



