30 ON THE CHILOPODA OF NORTH AMERICA. 



0. spinicatjda, n. sp. (figs. 7, 8.) — O. aurantiaca, capite polito, punctato ; scgmento basali depressione 

 magna triangular: mediana; antennis ? 16 articulatis, antice pubescentibus ; latninis dentalibus, labio 

 niandibulisque subprofunde punotatis, margine antico rotundato ; denticulis labialibus 4, parvis, arete 

 coadunatis, indistinctissicnis; labio medio antice subcarinato ; seuto postremo maximo, subprofunde 

 punctato, alteris fere bis majore. lateiibus rotundatis, marginibus lateralibus valde elevatis; pedibus pos- 

 tremis robustis, supra complanatis, intus complanatis et rude punctatis, articulo basali tibiali fere 

 sequali ; femora, tibia, tarsisque margine interiore superiore acuto et serrulato, femora tibiaque margine 

 interiore inferiore quoque acuto ct serrulato; processu angulari parvo, spina unica robusta acuta; 

 appendicibus analibus lateralibus angustis, postice truncatis, dense profunde punctatis, singula spina 

 unica apicali minutissima; squama preanali elongata, subprofunde punctata, media leviter canaliculata. 



The color varies greatly in depth of shade, but the two ends are almost always 

 darker than the intermediate portion of the body ; the feet, with the exception of last 

 pair, are generally lighter. The cephalic segment is slightly emarginate in front. 

 The suture between the true basilar segment and the prebasilar fold is very deep, 

 formed by two lines rapidly divergent from the centre, and at the central portion there 

 is cpuite a large triangular depression. In some the scuto-episcutal sutures are well 

 marked. The posterior border of the scuta is straight. The terminal scutum is 

 nearly twice as large 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, besides the terminal spine, is often furnished with one or 

 two small ones 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. 



Specimens belonging to Smithsonian Institution. 



264 

 347 



10 

 1 



South Illinois. R. Kennicott. 



Cook Co., 111. R. Kennicott. 



Uno. 1— 2J 

 .< o 



Gen. 6. TIIEATOPS, Newp.* 



" Ocelli distincti. Antennre breves, subulatae, 17 — articulatae. Segmentum cephalicum truncatum sub- 

 imbricatum ; margine labiali-denticulato. Pedum postremorum articulo magno, obconico, abbreviate 

 Pedum paria 21. Appendices anales laterales obtusse." 



T. postica, Newp. — " T. aurantiaca, ocellis inconspicuis lateralibus, dentibus 8 minutis, segmento postremo 

 maximo elongato quadrato lateribus rotundato medio profunde sulcato margine posteriore transverso, 

 pedibus postremis brevibus crassis rotundatis attenuatis; articulo basali brevissimo. Long. unc. 8-10." 



Crypt, postica, Say, Journ. A. N. S. Pliilad. ii. p. 112 ; Oiuvr. Entom. 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; Newp. Ann. 

 Mag. Nat. Hist. xiii. p. 110." 



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



" Hub. — In Georgia, Floridaque Orientali." 



*Linn. Trans, xix. p. 410. 



