THE MYRIAPODA OF NORTH AMERICA. 153 



The head is rather large, with a curved suture running transversely from one set of 

 ocelli to the other, which has its convexity directed posteriorly. The first scutum approxi- 

 mates the head in color, has its posterior margin strongly raised, and is only slightly 

 roughened. The other large scuta are very rough, with (sometimes indistinct, but gene- 

 rally well marked) rugae converging toward the median line anteriorly. The last scutum 

 is, however, without rugae, and but slightly roughened. It is much narrowed anteriorly 

 and posteriorly, and somewhat elongate. The preanal sternum is almost circular, with 

 two lateral curved impressions and a central shorter straight one, which are probably the 

 remains of the sutures between the plates of which it was composed during embryonic life. 

 The articular spines are rather strong. The smallest specimen has only twelve pairs of 

 eyes. It affords me great pleasure to dedicate this species to Mr. Xantus, through whose 

 "exhaustive collections" the rich fauna, of what was formerly a veritable terra incognita, 

 has been so rapidly developed. 



Ilah. Fort Tejon, Cal. — J. Xantus de Vesey. — Smithsonian Collection. 



B. BIPUNCTATUS. 



B. brunneus; segmento cephalico polito, margine postico elevato, labioque et sparse profunde et dense minute 

 punctatis; oeellis utrinque 18; antennis punctatis, sparse pilosis; laminis dentalibus brevibus, latis, denticulis 

 nigris aeutis 18 armatis, margine subrotundato ; scutis alternis majoribus capite simillime punctatis, politis, vis 

 asperatis, postice emarginatis ; scutis alternis minoribus postice margine recto et angulis baud productis ; sternis 

 politis ; pedibus punctatis, subrobustis. 



Brown ; cephalic segment polished, with its posterior margin elevated, together with the labium both sparsely 

 profoundly and densely minutely punctate ; ocelli on each side 18 ; antenna punctate, sparsely pilose ; dental 

 lamina short, broad, armed with 18 acute black dentieules, margin somewhat rounded; alternate larger scuta 

 punctate similarly to the head, polished, scarcely roughened, posteriorly emarginate; alternate lesser seuta with 

 their posterior margins straight, and their angles not produced ; sterna polished ; feet punctate, rather robust. 



B. bipunctatus, Wood, Journ. Acad. Nat. Sci., vol. v, new series, 1863, p. 16. 



The head is of moderate size, with the posterior margin slightly emarginate and not 

 elevated in the centre. The larger scuta are not deeply emarginate, but somewhat rough- 

 ened, with a suture on each side; the anterior portion of which is longitudinal, but the 

 posterior transverse. The transverse suture, running from one set of eyes to the other, 

 is not as well marked as in B. Xanti. The posterior scutum is rather deeply emarginate 

 behind. The preanal sternum is not as circular as in B. Xanti, but has similar markings. 



The appearance which I have described as densely minutely punctate is seen only under 

 a very high magnifying power, and is common in a greater or less degree to most species. 

 Length 1 inch. 



Hal. United States, west of Rocky Mountains. — Dr. Geo. Suckley, U. S. A. — Smithsonian Collection. 

 VOL. xm. — 20 



