MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 109 



The two median setii:' on ninth segment are separate, but arise from a slightlj' marked 

 common base, as in Stage I. Tlic sl<in is now finely spinous, tiie short spinules acute. (See PI. 

 LI. % S,n LIU, Hg. 1,/.) 



Stage III. — August 20. Length. 13-17 nun. The specific characters now appear, so that the 

 larviv may he easily identified. The black head is slightly narrower than the body. Prothoracic 

 plate distinct, entirely black, spinose on front edge. The thoracic horns are black, one-third 

 longer than the body is thick. The 1)ody is dark yellowish green, oi- rather olive green, with 

 two narroir i/eNoici-sA dorsal /i/wx, and a sul)dorsal and a lateral yellowish line on each side; the 

 underside of the bodj- is green. The spines are a little longer and sharper than before, other- 

 wise the larva is much as in Stage II, though the median spine on eighth segment is now 

 chitinized, solid, and black and as high as the diameter is broad (PI. LIII, fig. Ih). 



Suranal plate black, more spinose, the surface tubercles being larger and more prominent. 



Stage IV. — August 22-23. Length, 20 mm. Now the characters of the next last stage 

 appear. The body is entirely black, with four yellow stripes on each side, the subdorsal line 

 being the widest and firmest, and the infraspiracular line the most irregular and broken. The 

 under side of the bodj- is dull blackish. The horns are now a little larger and stouter than in 

 Stage III. The prothoracic plate has aline on each side. The suranal plate and sides of the anal 

 legs are sharply spinose, and the median spine on the ninth abdominal segment is higher, more 

 prominent than in Stage III (PI. LIII, fig. Ic-le). 



Sfaqc y. — Length, i2—ih mm. The body is thicker and larger than in ^i. ruhicimda. Head 

 black. Body and the prothoracic shield black, the surface of the plate rugose, with the spines 

 on the front edge low, smooth, not so well defined as in ^4. 7'uiicunda, as they are lower, while 

 the surface of the plate is rough with small short spines. The two horns are a little thicker and 

 longer than in A. ruhlcunda. rounded, not slightly forked at the end as in the previous stages, 

 but slightly bulbous; they are also rougher than usual on the surface, with rather stout, firm, 

 nearly atrophied spinules. The skin all over the body is rough, with numerous fine granulations, 

 bearing short minute seta;, the granulations in the other species not being so acute, and being 

 mostly without a seta. 



The ground color is black-brown; there are eight longitudinal deep yellow ocherous stripes, 

 the two dorsal ones narrowest; in one example wider than any of the others; the svibdorsal one 

 is straight, while the next one below (supraspiracular) is undulating; the one still below that 

 (infraspiracular) bearing the infraspiracular row of spines is divided l)y a narrow, irregular dark 

 line. A ventral yellow-ocher median stripe. The spiracles are black. 



The dorsal spines on the third thoracic segment are minute, low, not so high as thick, not 

 ending in a single spine, but are forked, ending in two short, sharp spinules. On abdominal seg- 

 ments 1-7 the dorsal spines are small, sharp, those on the seventh segment a little larger than 

 those on the preceding segments. Those on segments 8 and 9 (PI. LII, fig. 2; LIII, fig. 1/) are 

 decidedly larger than in ,1. nthtcanda, and much heavier and larger than in stage IV. The four 

 infraspiracular ones on segment 8 are of the same size, sharp, nearly twice as long as broad. 



Those on the ninth segment are from one-third to one-half larger than in A. ruhicwida, and 

 much larger and higher than in stage IV. The median one is a little more prominent than the 

 others, and decidedly forked at the end. The suranal plate is subcordate, with the two terminal 

 spines larger, though but little larger than the two on each side near the base, these belonging 

 to a group of three or four on each side, situated a little in from the edge near the base; the 

 surface is rugose, and with several spines differing in size (fig. if). The anal legs are blackish, 

 with numerous uneven spines around the edge, while over the central area are scattered fine 

 depressed spinules. All the spines, including the two horns, are stouter in proportion than in 

 any other species. Thoracic and abdominal legs all black, including the anal claspers. 



This is a very distinctly marked and colored species, and is easily recognized by the larger, 

 coarser spines and the alternating black and deep ocher yellow stripes. 



Another set of larva? received from Mr. Joutel, New York City, and reared at Brunswick, 

 Me., had already hatched July 2',t. They first molted August 9-10, the length between the molts 

 being nearlv the same as in the brood from Providence. 



