MEMOIRS Of^ THK NATIONAL ACADPLMY OF SCIENCES. 113 



tionably longer seta. There are two separate minute dorsal seta; on the nintii abdominal segment, 

 but they are much nearer together than the homologous ones on tlie eighth segment and arise 

 from a common slightly marked low eminence. 



The suranal plate (PI. LIII, tig. 2) is concolorous with the rest of the body, not pigmented in the 

 middle: the surface is smooth, with no conical spines, the four sette on each .side not arising from 

 definite tubercles, though there are two terminal, very small, microscopic, setiferous tubercles. 

 At the end of this stage the larva is green, and traces of the .seven lines appear. 



Stage 11. — Length. 9-10 mm. The head is now smaller in proportion than before, but still 

 black. Pi-othoracic shield bla<'k. In some of the larviB it is divided in the middle by a light 

 line. The two horns (tig. 4) are now shorter than l)efore in proportion to the body, being 

 about as long as the body is thick, and about two-thirds as long as the bodj' is broad. They are 

 now spinulated, about a dozen spiuules in sight from one side. The tip is more decidedly forked 

 than in stage I, and the seta? are short — about half as long as the spine is thick. All the primary 

 spines on the other segments are now much larger than before; stout, conical, of nearly uniform size. 

 those of the prothoracic segments being of the same size as those behind the succeeding segment. 

 There are three rows of spines on each side of the body, and the dorsal ones are no larger than 

 those of the subdorsal and subspiracular series. On the eighth abdominal segment there are two 

 widely separate dorsal spines, and two shorter ones on the ninth segment, with the median one 

 now chitinized, black, and as large as that on the eighth segment, but a little more obtuse, with 

 two tine setfe, showing the original double nature of this spine. On the tirst thoracic segment, 

 which is slightly narrower than the second, are two rounded black flattened conical tubercles, not 

 piliforous, and two smaller flatter ones behind. Two larger sul)triangular subdorsal black 

 tubercles give rise to three minute short hairs. They are represented on the thii'd thoracic 

 segment by two minute conical, black tubercles, the homologous ones on the abdominal segments 

 V)eing minute and greenish, tipped with black. Those on the sides of each segment arc larger, 

 acutely conical and black. On the eighth abdominal segment are four conical black tubercles. 

 two dorsal and two subdorsal, one on each side. On the ninth segment is a single median conical 

 tuliercle, not quite so high as those on the eight segment, but larger at the base. The subdorsal 

 tubei'cles on this segment are slightly larger than those on the eighth segment. Suranal plate 

 with the terminal spine very much larger than in stage I; black, chitinized; and on, each side, near 

 the middle, is a stout, short, conical black spine. On surface and sides are a few well marked 

 but small setiferous tubercles not visible in stage I. The suranal plftte is subcordate, being 

 excavated in front; behind it is subtriangular, with two black tubercles at the end, which are 

 smaller than those on the side in front of the middle; the suranal plate is greenish, like the 

 prothoracic segment, while the l)ody is tinged with yellowish, with eight faint rather broad 

 whitish longitudinal stripes. Along the underside of the body is a band, which varies from light 

 lemon-yellow to reddish, and is usually darker on the underside of abdominal segments 8 and it. 

 The spiracles are black. The thoracic legs are black. The anal legs are greenish, with a blackish 

 patch on the outside near the planta. 



In this and the next stage it continues to feed on the underside of the leaf. Directly alter 

 shedding the skin the head and horns are pale yellowish brown. 



At the end of this stage the body is somewhat reddish above, as well as beneath, while the 

 longitudinal stripes are reddish. 



Stdije HI. — Length, 12-14 nnn.. at end of the stage, '21 mm. The head is now chestnut red 

 to pale sienna brown; width, 2 mm. In this stage tirst appear two s(|uare black jiatchcs on the 

 prothoracic plate, and a trapezoidal patch on the suranal [)late. 



The two horns (PI. LII. tig. 4) ar(> now longer and slenderer than before, tapering ratiier 

 more, and with more setiferous spinules. On the top of the prothoracic segment are two scjuan; 

 black spots, in some cases there are four, extending back from each spine; a narrow one on each 

 side of the two square middle ones, while the two middle ones may be divided, making six in 

 all, or all may be wanting. The four jirothoracic spines are now more developed, forming low 

 conical warts. The dorsal ^i)ines on the last thoracic and tirst seven abdominal segments are 



