ON THE CHILOPODA OF NORTH AMERICA. 9 



tubercles or spines. Their border is everted, and generally crennlate and spinous. 

 The legs are very long and serrated by parallel rows of spinulae. They are also 

 furnished with rings, of long slender spines, encircling the joints. The sides have nin i 

 pairs of spiracles. — the openings into the tracheal vessels. The anal segment in the 

 female is elongate, and the external organs of generation are furnished with a pair of 

 forceps, replaced in the male by a pair of styliform appendages. The sterna (fifteen 

 in number) are small. It is very evident that the number of segments is fifteen, and 

 that each scutum, except the last, is formed by the coalition of two neighboring ones. 

 The pattern of coloration is peculiar to this family ; it consists of longitudinal stripes 

 on the body and annuli on the appendages. Green predominates. There has 

 as yet only one genus been found in this family, among which so great a unifor- 

 mity exists as to make the distinguishing of species a task of considerable difficulty. 



The color is probably a good specific character, but is seldom, if ever, preserved. 

 We have seen specimens of S. forceps changed almost immediately to green or blue, 

 or, more commonly, bright purple, by alcohol. 



All our descriptions of new species are drawn up from alcoholic specimens, and 

 therefore proper allowance should be made in estimating their accuracy as regards 

 coloration. 



Any anatomical characters are very obscure ; but Mr. Newport considers the pro- 

 portionate lengths of the metatarsal joints as constant, and we have found them so. as 

 far as our limited observations have gone. 



The lengths of the antenna and posterior pair of legs, as compared with the body, 

 are also probably good characters, but very liable to misinterpretation; for it is diffi- 

 cult, often impossible, to tell when the former are broken and when the latter are 

 imperfect, reproduced, appendages. Mr. Templeton, who first suggested these points, 

 also makes use of the size of the marginal spines of the scuta in his descriptions. The 

 peculiarities of the surface of the scuta also appear to be good secondary characters. 



Gen. 1. CERMATIA, IlUger. 



Caput magnum. Oculi prominentes. Stomata dorsalia lateribus incrassata. 

 Scutigera, Lamarck, Anirn. Sans. Vertb. 

 la, llafinesque, Annals of Nature. 



C. forceps. — C. viridi-brunnea, faseiis tribus longitudinalibus saturate viridibus; cnpite dense minute 

 punctate, antice breviter piloso, et linea di pressa longitudinale mediana et ante oculum utrinque altera 

 curvata, et altera trauversa inter oeulos, et postiee depressione lata insculpto; anteunis mandibuli 

 ferrugineis; seutis dense minute punctatis, spinulia numerosis asperatis, valde imbricatis, angulis ro- 

 tundatis, marginibus elevatis sed tenuibus et "spinis quam in Cerm. coleoptrata evidentiorib 

 lateribus plerumque rufescenti tinetis; femoribu anuulo uuico saturate viridi ; tibiis et tarsia 



biaunulatisj pedum pari postremo in mare corpore vix ', longiore (in femina bis longiore;) articulo 



a 



