THE MTRIAPODA OF NORTH AMERICA. 



217 



appendages (Fig. 43) are moderate. They have a small falciform spinule placed close to 

 their side. The terminal spine springs from a knob-like portion, which is quite hairy and 

 regularly curved. Its margin is irregularly notched near its middle, and its distal por- 

 tion is curiously fringed. The female appendages (Fig. 44) consist of a pair of bodies 

 shaped somewhat like the crest of a helmet. Along their free margin is an opening sur- 

 mounted by a double series of teeth-like processes. I think a careful examination will 

 convince any one that M. Saussure (loc, ell.) has described this species, under the name 

 of P. serratus, thinking it was the one indicated by Mr. Say. 



Length 1J inches. 



Huh. Pennsylvania, New Jersey, Illinois, &c. 



1*. CKRASINUS. 



P. dilute ccrasinus; dovso complanato; antennis modice pubesecntibus, nonnib.il elavatis, nonnihil brcvilms; 

 seutis squamis obsoletis ornatis, marginibus lateralibus serratis; appendicibus masculis spina terminale lata, 

 oblique truncata, utrinque proeessu longo setaoeo eurvato instructs. (Fig. 45.) 



Light-cherry red ; dorsum complanato; antennae moderately pubescent, somewhat olavatc, rather short; scuta 

 ornamented with obsolete squama), their lateral margins serrate ; terminal spine of the male appendages broad, 

 obliquely truncate, furnished on each side with a long, curved, setaceous process. 



P. fiERAsiNus, Wood, Proe. Acad. Nat. Sci., 1864, p. 8. 



Pig. 45. 



The head has the median furrow on its vertex illy pronounced. The anterior face is 

 sparsely pilose, and has its lower margin broadly but shallowly emarginatc. The scuta 

 have a double row of scales, obsolete, but otherwise similar to those of the 

 following species; sometimes these are entirely lost. The lateral margins 

 of the side plates are rounded slightly and minutely serrulate. They seldom 

 have more than three serratures on each side. The terminal scutum is trian- 

 gular, with its obtuse apex bent downwards. It is sparsely pilose. The legs 

 are quite hairy and light-colored. Their second joint is tumid. The appen- 

 dages (Tig. 45) in the male arc peculiar. The terminal spines arc broad and 

 short, and superiorly very obliquely truncated, with two small hamular processes. On 

 each side a long, seta-like process springs from the base. The outer, much the longer of 

 the two, throws an arch entirely over the short spines. The inner is straighter. They 

 both have one or two thorn-like excrescences. 



Hah. Oregon.' — Museum of Smithsonian Institution. 

 vol. xiii — 28 



