THE MYRIAPODA OF NORTH AMERICA. 



209 



occasionally reddish, as also the labrum and anterior margin of first segment. Posterior 

 third of each segment of a shining black. Stigmata and lateral stria; beneath quite con- 

 spicuous." 



"Remarks. — Resembles more Mus ornaius than 7". marginatus in the general proportions 

 of the body, but in the structure of the antennae and labrum comes nearer to /. margi- 



HUttlS." 



I. atratus, Girard, Marcy's Report, p. 274. 



S. UNCIQERUS. 



S. lsete brunneus, saturate-rubeo-brunneo annulatus ; capite sparse minute punetato et corrugato, antico puncto- 

 rum maximorum serie instructo; segmentis 50 — 53; scutis supra et eopiose punctatis et corrugatis; squama anale 

 triangula. 



Bright brown, annulated with deep reddish brown ; head sparsely minutely punctate and corrugate, anteriorly 

 furnished with a series of large puncta ; segments 50 — 53; scuta above both copiously punctate and corrugate; 

 anal scale triangular. 



S. uncigerus, Wood, Proc. Acad. Nat. Sci., 1864, p. 15. 



Fij;. 36. 



The color of this species is a bright brown, with an annulus of dark reddish brown on 

 the posterior border of each segment. The head is distinctly medianly canaliculate, 

 except in the centre, and has the row of dots on its anterior face, as in S. marginatus, but 

 is not as decidedly punctate elsewhere as in that species. The eyes are triangular. The 

 antenna 1 closely resemble those of S. marginatus, but are, perhaps, rather shorter and more 

 compressed. The first scutum is banded, both anteriorly and posteriorly. The lateral 

 processes, even the female, are almost wanting. The 

 second scutum is produced forwards as in S. marginatus. 

 The male appendages (Fig. 36) are composed of a yoke- 

 like piece and two outer parts, which it connects. The 

 central piece may be described as formed by two plates 

 (although but really one) meeting at an angle in the 

 centre and attached to the outer parts at their other 

 extremities. These outer articles are formed each as 

 follows: First. There is a large plate which is bent 

 around an inner basal piece, and is deeply notched late- 

 rally, but is produced anteriorly into a broad, almost 



rudely punctate plate, and posteriorly into a short, slender process, terminating in an 

 imperfect hook. This last process is sometimes obsolete. Second. Articulating with the 

 vol. xin. — 27 



