THE MYRIAPODA OF NORTH AMERICA. 183 



tremo (in mare ?) robusto, breve acuminata, articulis obconicis ; sternis suturis sterno-episternalibus et sulco mediano 

 luto impressis. 



Yellowisb orange, polished; body anteriorly attenuate ; head small; cephalic segment subtriangular, impunc- 

 tate; antennae moderately long, filiform, not acuminate, sparsely pilose, joints obconie; mandibles short, thick, 

 each with a rather large, conical denticule; labium short; anteriorly very e margin ate, impunctate; scuta some- 

 times with a very obsolete median line; feet rather long, pilose, slender, cylindrical, on each side 47 ; last pair 

 (in male?) robust, shortly acuminate, articles obconie; sterna impressed with a broad, median sulcus and sterno- 

 episternal sutures. 



StrIGAMIA PULVA, Sayer, Proc. A. N. S., vol. viii, p. 109. 



" " Wood, Journ. A. N. S., new series, 1863, vol. v, p.. 47. 



The color of this graceful little animal is an orange, approaching somewhat to fulvous. 

 The antenna? are very thread-like. Some of the specimens have the last pair of feet very 

 robust, with obconie joints. In others they are filiform and slender. The former are pro- 

 bably the males, the latter the females. I have, however, never been able to entirely 

 satisfy myself as to this, owing to the great difficulty of dissection. The median linear 

 depressions in the sterna are often dilated in their centre. 



Hub, Illinois, Pennsylvania, &e. 



S. BIDENS. 



S. aurautiaca, venuste polita ; segmento cephalieo triangulare, antice truncate, sparse late punctato, margine 

 antico postico nonnihil latiore; antennis brevibus, filiformibus, articulis obconicis; labio sparse late punctato, sulco 

 obsolete, margine antico denticulis duobus obsoletis obtusis annate; mandibulis intus minute unidentieulatis ; 

 suturis scuto-episcutalibus nullis; pedibus utrinque 76, cylindricis, paris postremi coxis magnis. foveis signatis ; 

 sternis suturis sterno-episternalibus et sulco mediano impressis; squama preanali convexa. 



Orange, beautifully polished ; cephalic segment triangular, anteriorly truncate, sparsely broadly punctate; the 

 anterior margin somewhat broader than the posterior; antennae short, filiform, their joints obconieal ; labium 

 sparsely broadly punctate, sulcus obsolete, anterior margin armed sometimes with two obtuse, obsolete denticules ; 

 mandibles within minutely unidenticulate; scuto-episcutal sutures absent; feet on each side 76, cylindrical ; coxte 

 of last pair large and marked with little pits; sterna impressed with sterno epistemal sutures and a median sulcus; 

 preanal scale convex. 



S. isidens, Wood, Journ. A. N. S., new series, 1S63, vol. v, p. 47. 



The coxae of the last pair of feet are very large. Their inferior surface is convex, and 

 indented with from twenty to thirty small, round pits, irregularly arranged in rows. The 

 remainder of the feet are, in our specimen, slender. I presume that the above character 

 is persistent in both sexes, but cannot be certain on. this point. There is a single speci- 

 men in the Museum of the Academy, labelled as having been found near Philadelphia by 

 Joseph Leidy, M.U. I have never met with it whilst collecting. The length is about an 

 inch and a half. 



