100 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



tilt' middle. Conipaiod w itli .1. virginieiixis of this .stage the tubercle.s of the plate, as well as the 

 rest of the body, are smaller, while those on the suranal plate are larger than in ^-1. senatoria. 



While at first there are no characteristic markings, at the end of this stage appear faint 

 traces of the eight dark lines, which are more pronounced in the next stage. 



One larva molted July 24, and two or three molted for the first time July ?>(>. When uhout 

 to molt it was I'i mm. in length. 



Sfai/c II. — Length, 7 mm.; at the end of the stage. 10 mm. Head nearly twice as large as 

 before and still black. The body is now dark, including the prothoracic shield, and the two horns 

 and all the tubercles are also black, as well as the sui'anal plate and abdominal legs, including 

 a})doniinul segments 9 and 10. (Compare PI. L, fig. "iit ; LII, fig. 3ff.) 



At first after hatching the body is pale, the future dark portions not yet being pigmented, 

 l)ut toward the end of the stage the »even Mack lines hecome distinct. The spines now Itecome 

 large and well developed, but short. The underside of the body is livid green. 



The two horns are t trice as himj as in the first stage. (PI. LI, fig. 2.) 



Of the seven dark lines or stripes the medio-dor.sal or vascular line is narrow, while the one 

 on each side is much wider; the next below (supraspiracular or subdorsal, containing the series 

 of spines of that region) is not so wide or quite so dark as the two wider dorsal ones. The 

 spiraculur line (including the spiracles) is narrow, and a little fainter. There are no lines below 

 this, and the underside of the body is not pigmented. 



So far as I can see, the lines appear simultaneously along the whole body; they differ in inten- 

 sitj-, becoming darker toward the middle of the stage, the pigment being deposited more abun- 

 dantly after exposure to the light. 



Stage III. — Described July 27, when just about to molt. Length, 20 nun.: length of horns, 

 7 nmi.; width of head, 2 mm. The head is now Indian or cherry red. The body is rather dark, 

 livid, cherry red, but without the white granulations of stage IV. 



The spines on prothoracic segment black, more jagged, forked, and j)()inted than in stage 

 IV (where they are rounded at the tip and bear a single seta). 



The two horns with much longer, slenderer barbs than in stage IV. 



Suranal plate black above, lieneath reddish, the black, upper surface contrasting with the 

 didl. reddish hue of the ))od_v. Anal legs with a large, I'ed, triangular spot inclosed in the dark 

 edge. The mid-abdominal legs dull cherr}- red, with a black spot above the planta. There are 

 faint indications of a dark spiracular line. The spiracles are blackish, but smaller than in 

 stage IV. (For details of the armature see PI. L. fig. 'Ih. 2c: LI. tig. 2h; LII, fig. ^>/^) 



In stag(> III there is a decided change in the markings; the dark lines of stage II are now 

 nnicli motiiticd. The}' have become faint, and only traces of them remain, while a new kind of 

 ornamentation, the white graiuilations, appear. With the disappearance of the dark stripes, the 

 traces of the two longitudinal pink lines now appear, a new plan of coloration being thus 

 installed and not apparently inherited from a previous ancestry. The three dorsal lines are 

 now ])lended together into a broad, pale, reddish Imnd. and the ])ale or wdiitish line on each side 

 of the head is emphasized, this becoming the upper oue of the two pink lines of the later stages. 



Stage IV. — Length, 21-25 mm.; length of the mesothoracic horns, 10 mm. The horns are 

 longer and less spinulated than in stage III, and the body is black, dotted with porcelain-white, 

 tuieven setiferous granulations. Head Indian red or dull cherry red. Protltoracie segnwnt auth 

 ,s/,/' large stent forl-nl sjiiiirs. where those of ^4. rirginiensis are small, almost rudimentary, and 

 they are larger than in the liual stage. These spines vary, however, in being rounded, not 

 forked, and bearing a single seta. Also the porcelain white granulations are much larger than 

 ill .1. i'lr</iiii> asis. The horns on the second thoracic segment are movable and much longer 

 than in the last stage, being nearly twice as long in proportion. The dorsal spines on all the 

 succeeding segments are of nearly the same size, being nearly one-half as long as the bod}- is 

 thick; those on the third thoracic segment are unevenly forked and of the same size as those of 

 the sixth and eighth abdominal segments; tho.se on segments 1-5 being a little smaller; those on 

 the third thoracic segment are more regularly bihd than the abdominal ones, whicdi have the 

 smaller fork lower down. 4'lie single median spine on the ninth segment is no larger than either 



