IS!) THE MYRIAPODA OF NORTH AMERICA. 



S. MACUIjATICKPS. 



S. sordide aurantiaca, polita ; corporo robusto, subsemicylindrico, antice modice attenuato; capite modice parvo, 

 obscure saturate rubro, minute albomaculato, in lateribus sparse piloso; antennis longis, leviter pubescentibus, haud 



acuuiinatis ; mandibulis crassis, obscure quadridentatis, pilis paucis; denticul tico utrinque magno, conico ; labio 



impunctato, atitice vix emarginato, medio canaliculate; pedibus modice longis, gracilibus, subcompressis, utrinque 

 77, et superficie ventrali sordide flavis; scutis lsevibus sine suturis; sternis laevibus, suturis sterno-episternalibus 

 valde impressis et plerumque postice depressionum subovatarum transversarum pari ; pedibus postreruis ("stylis 

 analibus") (in mare solum ?) robustissimis, supra subcomplanatis, subtus convexis, acuuiinatis. 



Dirty orange, polished; body robust, subsemicylindrical, anteriorly moderately attenuate; head rather small, 

 obscurely deep red, minutely spotted with white, sparsely pilose on the sides; antennae long, lightly pubescent, 

 not acuminate; mandibles thick, obscurely quadridentatc, with a few hairs; anterior denticule on each side large, 

 conical ; labium impunctate, anteriorly scarcely etnarginate, medianly canaliculate; feet rather long, slender, sub- 

 compressed, on each side 77, together with the ventral surface dirty yellow; scuta smooth, without sutures; sterna 

 smooth, strongly impressed with the sterno-episternal sutures, and generally with a pair of irregularly ovate, trans- 

 verse depressions; last pair of feet ("anal styles") (in male only?) very robust, above subcomplanate, below 

 convex, acuminate. 



S. maculaticeps, Wood, Journ. A. N. S., new series, vol. v, 1863, p. 48. 



The cephalic segment is slightly narrowed anteriorly, and the upper surface of the whole 

 head is marked with very small whitish dots. The anterior and posterior extremities of 

 the body are perhaps a little darker in color than the intervening portion. The inferior 

 aspect of the head is of the same color as the superior, contrasting with the under surface 

 of the body. Near the posterior border of each sterna there is a pair of subequal 

 oval transverse depressions. The legs are almost destitute of hair, having occasionally. 

 however, a few very short ones. Length, *2i inches. 



Hab. Upper Colorado. II. B. Mollhausen. — Smithsonian Collection. 



S. LATICEPS. 



S. dilute aurantiaca; capite magno, impunctato; segmento cephalico lato, breve, transverso, quinqueangulato, 

 Begmentis basali subbasalique marginibus curvatis et angulis anticis prolongatis; antennis brevibus, crassis, cylin- 

 dricis, antice pubescentibus; labio breve, nonnihil convexo, haud canaliculate; mandibulis parvis, singula intus 

 denticulo obtuso indistincto; pedibus subcompressis, gracilibus, utrinque SI, pari postremo (in mare solum ?) non- 

 nihil crasso, cylindrico, haud acuminate, coxis raagnis ; sternis depressionc lineari-ovata transversa et suturis sterno- 

 episternalibus signatis; squama preanali valde canaliculata, postice valde emarginata, angulis posticis subaoutis. 



Light orange; head largo, impunctate ; cephalic segment broad, short, transverse, quinqueangulatc ; basal and 



subbasal segments with their margins curved and anterior angles prolonged; antennae short, thick, cylindrical, 

 anteriorly pubescent; labium short, somewhat convex, not canaliculate; mandibles small, each with an indistinct, 

 obtuse tooth on inner surface ; feet subcompressed, slender, 81 on each side; last pair (in male alone:') somewhat 

 thickened, cylindrical, n a acuminate, with large coxae; sterna marked with a transverse linear-ovate depression 



