266 MEMOIKS OF THE NATIO>TAL ACADEMY OF SCIENCES. 



occurred at I'lovidence on tlio wild cheiry in September. Ilellins states that the eggs of 

 C. rinula are l.<> to almost 2 mm. in diameter, and that the larva at its tirst molt is not more 

 than 7 mm. long. I'ossibly the first stage was not observed by ]\Ir. Bridgliam, and the following 

 descrii)tion should ai)ply to the second. Comjiare also Dyar's detailed descri])tion : 



E(j(i. — " Less than hcmisiilierical — obtusely eonoidal, the base llat; minutely shagreened, color 

 black; a little lustrous, but not shiny. Laid singly on either surface of the leaf." (Dyar.) 



Cocoon. — Oval elliptical flattened, but central area well rounded; the edges broad and thin; 

 spun of light drab silk; attached to side of breeding box or to bark of tree, and thus easily 

 mistaken for an excrescence on tlie tree; being a case of jjrotective mimicry. 



Larrit: Stage II. — Length in all, 1.5 mm. September 4. Head only as wide as the body behind 

 the middle. The filamental anal legs, or stemapods,' as we may designate them, are now more 

 than slightly half as long as the body. The hornlike tubercles on the prothoracic segment are 

 slightly longer than in the second stage. The head and body are dark reddish brown above, the 

 filamental anal legs with two broad, pale, greenish rings. All the other abdominal legs are 

 green; the green patch extends from the underside of the tirst abdominal segment back over the 

 third to eighth pair of spiracles, and underneath to the end of the body. 



Stage II. — Length of body, I-i mm.; of stemapods, 7-S mm., and of Hagella, .'! mm. September 

 11. The head is rough and warty, the small warts bearing tine hairs. On the front toward the 

 vertex are four pai)iriiform, piliferous warts of the same size and shape as those on the i)rothoracic 

 projections, and concolorous with the dark brown head. These spines are represented in the 

 other species [C. occidentalis) from the willow only by very minute warts, bearing long, tapering 

 bristles. The prothoracic segment is very wide and large, the well-defined cervical shield very 

 broad, and ending on each side in a large, stout tuberculated horn, bearing about twelve 

 piliferous, papilliform tubercles, there being a rude whorl of .spines in the middle of the horn, the 

 others growing out at the end. There are four coarse piliferous warts on the hinder edge of 

 the cervical shield. 



Along the body are scattered coarse i)iliferous warts, the dorsal four being arranged in a 

 trapezoid. The stemapods are coarsely spined (more so than in ('. ore idcii talis). 



A peculiarity of the genus is the pair of very long papilliform infraanal tubercles, situated 

 under the suranal plate, and ending in two long, stiff, sharp bristles.- The suranal plate is long 

 and narrow, well rounded, and the surface is provided with high ])ai)illiform, i)iliferous warts. 



In this species the head and the prothoracic horns above and beneath are reddish brown, the 

 latter in C. occidentalis being yellowish beneath, the two species by this mark being easily 

 -separated. 



The body is now more green on the sides, the green hue encroaching on the back and nearly 

 meeting on the third thoracic segment. Only the fourth abdominal segment is wholly dark seen 

 from above, and the green api)roximates high uj) on the sides of the sixth and seventh segments. 



Stage III. — September 17. Length of body, 1!) mm. and of stemapods, 12 mm. The body is 

 now much thicker than before. The head is now smooth, with no traces of ])iliferons warts or of 

 hairs representing them. The head is now larger in proportion to the body and paler red, 



'The term "tails" or caudal filaments is too vague for these highly modified anal legs; hence we propose the 

 terra siemapoda or stemapods for those of C'erura aud Hetorocampa. The derivation is Gr. ar/t/jn, lilainent ; -o/f, 

 TToildf, leg or foot. Mr. J. Hellius, referring to these organs in Buckler's L.arviB of the British Butterlties and 

 Moths (Roy Soc, ii, 138), remarks "but now through Dr. T. A. Chapman's good teaching I regard them as dorsal 

 appendages, somewhat after the fashion of the jinal spines of the larv:c of the Satyrida-." This, I am satislied, is an 

 error. After repeated comparisons of tlie filamental anal legs of Cerura with those of Hetcrocampn murlhiaia, and 

 comparing these with the greatly elongated anal legs of young II. iiiiiciilor as figured by I'opt-noe, aud iakiug into 

 account the structure aud homologies of the suranal anil )>reanal daps, one can scarcely doubt that those of Cerura 

 are moilitieil anal legs. 



It sliould be also remarked tliat this was the view of Latreillo (Gen. Crust., et Insect., ISllii. ]i. L'lll). who Ueliues 

 the genus thus: Krucn pedibun analihiix in raiiditm /(irciilaiii trKiin/nniiatix. 



- The use of these I find explained by Mr. Hellius in his description of the larva of C. hijida iu Buckler's Larv:e 

 of British Btitterllies and Moths, ii, p. 112, as follows : " At the tip of the anal llap are two sbarj) jiolnts, aud auotlier 

 pair underneath, which are used to throw the pellets of frass to a distance." .Similar dungforks are very generally 

 present in georaetrid larvre, the inl'raaual papillifonu tubercles being well developed, though we have not seen 

 them iu use. (See also Dyar.) 



