NATURAL SCIENCES OF PHILADELPHIA. 9 



The scuta appear to have a narrow edging of black posteriorly. The terminal 

 scutum is subtriangular, very prolonged and very thick posteriorly. We have 

 never had an opportunity of examining the male genital organs. Ihose of the 

 female are very pilose, and are formed of two portions. They are contracted 

 at their bases, and expanded above, somewhat as a reversed flattened cone. 

 The basal piece is thicker, and less hairy than the other. The distal piece is 

 set into it, and has along the free extremity an opeuing. 

 Hab. Oregon. Museum of the Smithsonian. 



Subgenus LEPTODESMUS. 



P. PLACIDUS. 



P. olivaceo-brunneus, scutis plerumque nigro vittatis ; laminis lateralibus 

 parvis, dilute brunneis ; pedibus saturate olivaceis ; sternis dilute brunneis ; 

 appendicibus genitalibus masculis, valde elongatis ; spiua terminale magna, in 

 spiram ducta et spinulo basali longissimo falciforme et altero laterale breve 

 robusto instructa, margine partim acute serrato, partim integro. 



The head is dark colored. Besides its median furrow, it is also ornamented 

 with a pair of sometimes illy pronounced punctae on each side of the ver- 

 tex. Its inferior border is rather broadly emarginate. The antennae are 

 elongate, dark brown, and tipped with black. The anal scutum agrees with 

 the others in color. It is triangular, with its apex truncate, obscurely emar- 

 ginate and decurvate. The male genital appendages are strikingly elongate. 

 The terminal spine is nearly black. It is bent spirafly on itself, but after per- 

 forming a little more than an entire turn is nearly horizontal for some length. 

 It is flattened, with its superior surface somewhat umbonate. It ends in a 

 thick, blunt, spine-like process. The proximal portion of the anterior margin 

 is acutely serrate. From the edge projects a short thorn-like spinule, and 

 from the base a long, slender falciform spine. 



Length, one and a quarter inches. 



Hab. Michigan. Prof. Miles. 



P. floridus, var. ? 



P. atro-castaneus ; scutisj>ostice rubro-aurantiaco marginatis ; laminis later- 

 alibus parvis, laete rubro-aurantiacis ; appendicibus genitalibus, masculis P. 

 placidi illis similibus. 



The head is lighter colored than the body. It is medianly canaliculate, 

 with a pair of punctations on each side of its vertex. Its inferior border is 

 broadly emarginate. The antennae are rather long and slender, very slightly 

 clavate, light brown, and distally tipped with black. The scuta are smooth, 

 beautifully polished, and not corrugate. The side plates are distant, quite 

 small, and nearly horizontal. Their anterior angles are rounded. The anal 

 scutum is prolonged, and is sometimes wholly, sometimes partially orange. It 

 is triangular, with its apex truncate and slightly emarginate, and its sides 

 curved. It projects posteriorly, and is bent downwards. The feet are cylin- 

 drical, yellow, and somewhat pilose. The male genital appendages resemble 

 those of P. placidus, except in color. They are yellowish. Those of the female 

 consist of a pair of short, blunt processes. Each of these has a basal portion into 

 which is set a short somewhat flattened body, with an obscure linear opening 

 traversing its distai surface. From the junction of these two parts springs a 

 heavy fringe of long, coarse hair. P. floridus is very possibly a distinct spe- 

 cies from F. placidus. I have seen but a single individual of the latter. The 

 general appearance of the two is so dissimilar, as to incline me to the be- 

 lief of their distinctness. But they agree well as to their genitalia, and a suite 

 of specimens might show their identity. 



Length one and a quarter inches. 



Hab. Michigan. Prof. Miles. 



1864.] 



