Page:Wood 1865 - The Myriapoda of North America.djvu/38

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THE MYRIAPODA OF NORTH AMERICA.
173

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 operation 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 maxillse and maxillary 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 The exuvia has most of the posterior segments entire, showing that the occupant has been withdrawn from it like a hand from a glove.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 antennæ 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.

Hab. The Atlantic United States.


S. gracilis.

S. ferruginea; capite 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 vix punctatis; pedibus postremis gracilibus, elongatis, singulo spinis duabus S. sexspinosæ illis similimis, articulo basali tibiali longiore, articulis tribus ultirais pubescentibus; appendicibus analibus lateralibus elongatis, rude punctatis, singula spina apicali unica (interdum bifida) alteraque minutissima in angulo superiore posteriore; squama preanali elongata, punctata, postice late emarginata. (Fig. 14.)

Ferruginous; head and labium lightly punctate, cephalic segment subovate; antennæ pubescent; anterior margin of the labium rather narrow, with oblique sides, emarginate apex, and acute angles; feet yellow, subcompressed; 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. S., new series, 1863, vol. v, p. 38.

Fig. 14
The color in all of our specimens is lighter and more ferruginous than the typical color