70 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Staye IV. — It is possible that the hirva described by me in the Proceedings of the American 

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

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

 being differentiated 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 succeeding segment. 



I therefore copy Doctor Jewett's description of this stage, which gives the markings antl 

 colors: 



" Larv;v> passed their third niult June 13, three-fourths to seven-eighths of an inch long, 

 nearly cylindrical, 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 

 larvre and green in others. The only other changes are that the horn-shaped tubercles on the 

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

 the appearance of burnished silver externally, and the stigmatiil 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 larvre 

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

 In some larvae the stigmatal space has numerous small black tubercles on each segment: in 

 others there ai"e no black tu])ercles." 



Stage F(figs. 3, '6u). — Not seen to molt, iiut it probably occurred August 1 or 2. Length, 

 25-28 mm. The head is, as before, with two yellow stripes, one on each side, and Vjordered more 

 or less on each side, especially in front, with black. The four pairs of thoracic horns ai'e now 

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

 forked tips, and yellowish green 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-i'ed as the thoracic horns. The sharp, stout, spine-like tubercles on the fourth 

 and sixth aVidominal 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 bands are much as before. The increase in size of thi> stage 

 over the preceding one is noticeable. 



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

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

 place at the time of the second molt. 



Ill a larva 20 mm. long, and probably of stage IV, the lateral band is tricolored, marked 

 with straw-yellow, the yellow inclosing the base of the black spines. Jewett says: "The legs of 

 some larvic are green and of others brown. Prolegs of .some green and in others green tipped 

 with brown. In some larva' the stigmatal space has numerous small, l)lack tubercles on each 

 segment; in othei's there are no ])lack tubercles." 



The following description of another larva, drawn up October li» and in tlic last stage, may 

 be useful: 



I'l. XL\'I. tig. 3. — Length, 24 mm. Body rather thick. Head remarkably Sphinx or 

 Smerintiuis-like, as wide as the body, flattened in front, broad below al)out the mouth, but nar- 

 rowing toward the vertex, as in Sphinx; the skin rough; with two lateral, rather broad, 3'ellow 

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

 across the upper division of the clypeus is a blackish band which adjoins a black })lotch on each 

 side, and which touches the yellow line. Labrum ])ale yellowish, l)lackish in the middle; eye- 

 patch and mandibles black. 



o Jewett says tlie spines are "brown in some larvse and green in others." 



