THE MYRIAPODA OF NORTH AMERICA. ll'S 



legs are marked with an elongate whitish blotch. 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 maxillae 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 withdrawn from it like a hand from a glove.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 large*, stouter, 

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



Hull. The Atlantic United States. 



S. GRACILIS. 



S. f'erruginea; eapite labioque leviter punctatis, segmento-cephalico subovato ; antennis pubescentibus; labii 

 margine antico modice angusto, lateribus obliquis apice emarginato et angulis acutis ; pedibus flavis, subcompressis ; 

 scutis sternisque vis punctatis; pedibus postremis graeilibus, elongatis, singulo spinis duabus S. sexspinosae illis 

 siinilimis, articulo basali tibial! longiore, articulis tribus ultiinis pubescentibus; appendicibus analibus lateralibus 

 elongatis, rude punctatis, singula spina apieali unica (interdum bifida) alteraque tninutissinia in angulo superiore 

 posteriore ; squama preanali elongata, punctata, postice late emarginata. (Fig. 14.) 



Ferruginous; head and labium lightly punctate, cephalic segment subovate; antenna: pubescent; anterior 

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

 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, Woo,/, Journ. A. N. S., new series, 1863, vol. v, p. 38. 



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



