THE MYRIAPODA OF NORTH AMERICA. 171 



as any of the others, deeply punctate, and without a sulcus or any traces of the sutures. 

 The last pair" of legs are dark in color, short and very robust ; their basilar joint is often 

 furnished with one or two small spines, besides the terminal, on either the inferior or 

 superior internal margin. They present the peculiar crossing of the nails found in the 

 other species. The other legs are somewhat compressed. Length, 2i inches. 



Huh. South Illinois, West Pennsylvania. Smithsonian Collection. 



Gen. 6. TIIEATOPS, Neirp* 



"Ocelli distincti. Antennas breves, subulatas, 17 — articulatae. ' Segmentum ccphalicutu truneatum subimbri- 

 catum ; margine labiali denticulato. Pedum postremorum articulus magnus, obconicus, abbi'eviatus. Pedum paria 

 21. Appendices anales laterales obtusaj." 



Eyes distinct. Antennas short, subulate, 17 articulate. Segments cephalic, truncate, subimbricate ; labial 

 margin denticulate. Joint of the last feet large, obconical, abbreviated. Pairs of feet 21. Lateral anal appen- 

 dages obtuse. 



T. POSTICA. 



" T. aurantiaca, ocellis iuconspicuis lateralibus, dentibus 8 minutis, segmento postremo maximo elongato quad- 

 rate lateribus rotundato medio profunde sulcata margine posteriore transverso, pedibus postremis brevibus crassis 

 rotundatis attenuatis ; articulo basali brevissimo. Long. unc. 8-10." 



Orange, ocelli lateral not conspicuous; teeth 8 minute; last segment very large, elongate, quadrate, with its 

 sides rounded medianly; profoundly sulcate, with its posterior margin transverse; last feet short, thick, rounded 

 attenuate; basal joint very short. Length, 8-10 inches. 



Crypt, postica, Say, Journ. A. N. S., Philada., ii, p. 112 ; (Euvr. Entoni. i, p. 24 ; Gervais, Ann. Sci. Nat. 

 Janv., 1837, p. 51, sp. 5; Apt. iv, p. 294. 

 " Lucas, Hist. Nat. Anim. Artie, p. 547, sp. 5. 



" Newport, Ann. Mag. Nat. Hist., xiii, p. 110. 



Theatops postica, Newport, Linn, Trans., xix, p. 410; Catal. British Mus. (Myriap.), p. 61. 

 " Wood, Journ. A. N. S., new series, vol. v, 1863, p. 37. 



" Rah. In Georgia, Floridaque Orientali." 



" The mandibles are short, thick, and have a distinct basal tooth ; the dental plates are 

 elongated and widely separated ; the teeth 8, minute but distinct. The basal joint of the 

 posterior pair of legs much shorter than the second, which is twice as long as the succeed- 

 ing joints. The lateral anal appendages deeply punctured. Preanal scale flat, with a 

 median longitudinal sulcus and scattered punctures, with the margin straight." 



I have never seen a specimen of this species. 



* Linn. Trans., xix, p. 410. 



