THE MYRIAPODA OF NORTH AMERICA. 



173 



legs are marked with an elongate whitish hlotch. The preanal scale is rather short, and 

 much narrowed posteriorly. I have examined a number of specimens, and have found 

 the articular spine in few. I recently observed an individual just completing the ope- 

 ration of shedding his skin. This was crowded back so as to cover only the last two or 

 three segments, giving the animal a very peculiar appearance. He soon, however, with 

 many contortions, drew himself out of the old garment. On examining it, I found that 

 it contained the derm of the head and all its appendages, even to the maxilla? and maxil- 

 lary palpi. The anterior portion of the skin was so torn as to show that the process of 

 shedding probably commenced by the creature's withdrawing its head from its case, and 

 then thrusting it out between some of the anterior sterna, completing the process by 

 pushing the skin back with its legs aiding them by a peculiar wriggling motion. The 

 exuvia has most of the posterior segments entire, showing that the occupant has been 

 withdrawn from it like a hand from a glove. The animal is of a milk-white color, with 

 the antenna; pubescent, and the lateral anal appendages not elongate and without spines.- 

 The lower spine on basal joint of last pair of legs is very small, and the upper one scarcely 

 perceptible. I once had the pleasure of observing a female guarding the young. She laid 

 on her side, with her body coiled around them, and, by a rapid, cilia-like action of her 

 feet, would pass them along and arrange them to suit her. This species is one of the most 

 common chilopods around Philadelphia. The Southern specimens are much larger, stouter, 

 and more highly colored than those from colder regions. Length, 2 inches. 



Ilab. The Atlantic United States. 



S. GBA0ILI8. 



8. ferrugineaj eapitc labioque levitcr punetatis, scgmento-cephalieo subovato; antennis pubesccntibus ; labu 

 margine antico modice angnsto, lateribus obliquis apiec emarginato et angulis acutis; pedibus flavis, subcompressis ; 

 scut is sternisque vix punetatis; pedibus postremia gracilibus, elongatia, singulo spinis duabus S. sexspinosas lllis 

 similimis, articulo basali tibiali longiore, articulis tribus ultimis pubeseentibus ; appondieibus analibus lateralibus 

 elongatis, rudo punetatis, singula spina apieali unioa (intordum bifida) alteraquc minutissiina in angulo superiore 

 posteriorc ; squama preanali elongata, punctata, posticc late emarginata. (Fig- M.) 



Ferruginous; head and labium lightly punctate, cephalic segment subovato; antennae pubescent; anterior 

 margin of the labium rather narrow, with oblique sides, emarginate apex, and acute angles; feet yellow, suboom- 

 pressed; scuta and sterna scarcely punctate; last feet slender, elongate, each with two spines very similar to those 

 of S. sexspinosa; basal joint longer than the tibial; three last joints pubescent; lateral anal appendages elongate, 

 rudely punctate, each with a single apical spine (sometimes bifid), and another, very minute, upon the superior 

 posterior angle; preanal scale elongate, punctate, posteriorly broadly emarginate. 



S. GRACILIS, Wood, Journ. A. N. 8., new series, 1863, vol. v, p. 38. 



The color in all of our specimens is lighter and more ferruginous than the typical color 



