A STUDY OF CERTAIN CATERPILLARS. 1235 



surprising. Attention lias already been drawn to tliis point in a general 

 way (pp. 804-808), imt it is true to so marked an extent in the caterpil- 

 lars of our swallow-tails that it seems well to recur to it in a more precise 

 manner ; for if in their earliest stages these caterpillars were only large 

 enough to have all their peculiarities readily seen by the naked eye, more 

 attention would long ago have been given them. It is also important on 

 other grounds. Weismann has mcntioiii'<l the desirahilitv of studviiig the 

 early stages of these caterpillars in particular, to acquirx; a knowledge of 

 their phylogeny, and they have formed the subject of an extended but still 

 incomplete paper by Ciruber,* somewhat barren in results from its incom- 

 pleteness, and in some particulars from its inaccuracy. The more com- 

 plete material now at hand, studied almost entirely from fresh objects, the 

 extraordinary variety among our New England forms, and the curious fact 

 that these cover almost the entire rang-e of variation known amona: the 

 caterpillars of Pa[)ilionidi the world over, lend special interest to such an 

 enquiry. 



I propose in the first place to give for each of the six species of our 

 fiiuna, each representing a distinct genus, as succinct an account as pos- 

 sible of the several important changes ; next to summarize from this the 

 leading lines along which the changes have occurred ; and finally to draw 

 from the facts such conclusions as seem admissible. T follow the order of 

 the text of the present work. 



The caterpillar of Laertias at birth is uniformly cylindrical, of a uniform 

 dark brown, covered with several rows of conical warts of nearlv uniform 

 size, most of them bearing a single bristle, a few, on the thoracic segments 

 and just above the abdominal legs, more than one. In its second stage the 

 shape and coloring are the same as before, but the clothing of the body is 

 greatly changed, for all the waits bearing single bristles have disappeared, 

 together with their bristles, and so have the bristles of the other Avarts, but 

 in these latter instances the warts remain, and have become short, fleshy, 

 often brightly colored filaments ; while to take the place of the simpler 

 warts a new and independent series of fleshy filaments has arisen between 

 the two series which disappeared. The remaining stages are much the same 

 as this, only the filaments at the extremities of the body grow longer and 

 longer with each stage, more and more highly colored : a suprastigmatal 

 scries of coral red spots is introduced in the fourth stage on some of the 

 abdominal segments ; and finallv, in the last two stages, the thoracic seo"- 

 ments taper forwards markedly. 



The new-born Iphiclidos is cylindrical, but a little larger in front than 

 behind, of a nearly uniform dark leaden color, darker, however, on the front 

 h.ilf than behind, covered with rounded warts arranged in several rows, a 

 few at the extremities slightly larger than the others, most of them support- 



•Jeii. zeiUchr. narturw.. xvii; Papilio, iv. 



