NATURAL SCIENCES OP PHILADELPHIA. 7 



Hab. Michigan ; Prof. Miles. Trenton Falls, New York ; Mu3. Comp. 

 Zoology, D. Mack. 



P. BIPIDDS. 



P. rubro castaneus, segmentis et antice et postice late fulvo-marginatis, la- 

 minis lateralibus dilute fulvis ; scuto anale triangulare, apice truncato et de- 

 curvato ; appendicibus genitalibus masculis elongatis, pilosis ; spina terminale 

 gracillima, proxima cylindracea, ultima bifida et noanihil abrupte curvata, 

 spinulo basale gracillimo parvo armata. 



All of my specimens have been preserved for a length of time in alcohol, so 

 that the description of color is not as accurate as it should be. The anterior 

 aspect of the head is much lighter than the vertex, which is mediauly strongly 

 canaliculate. The antennae are dilute fulvous, are rather longer than in 

 P. virginiemis, and are distally, sparsely and shortly pilose. The spicules on 

 the distal ends of the first and second joints of the long and slender feet are 

 robust, but are often obsolete anteriorly. The terminal scutum has several 

 punctae closely resembling pores. The preanal scale is triangular; it has 

 two little elevations surmounted by a punctum. The male genital appendages 

 are elongate. Their terminal spine is very slender and cylindrical in its prox- 

 imal portion ; distally it is bifid and strongly curved. It is ornated with 

 a very slender curved basal spinule. 



Hab. Georgia; Museum of Comp. Zoology, Dr. LeConte. Texas; Collection 

 of Smithsonian, G. Wurdeman. 



P. CRASSICUTIS. 



P. maximus, robustus; scutis enormiter subrude punctatis; appendicibus 

 genitalibus masculis, singula spinis quatuor armata ; duobus magnis, parvis 

 duobus. 



The color of all the specimens is light testaceous ; with, in many, a dark dor- 

 sal line. It is very possible that the alcohol, in which they have been long 

 preserved, may have destroyed the original color. The animal is very large 

 and robust, and has its outer armor and side plates very heavy. The head on 

 its upper surface has a distinct median furrow, and on its lower a broadly 

 lineal, oblique depression on each side. The inferior margin is rather broadly 

 and deeply emarginate. The lateral lamina are rather short. The female 

 genital appendages are a pair of small, pyramidal, pilose bodies, whose 

 apices are split into three or four very minute mameloid processes. The 

 male organs are large, and distally very hairy. They are each armed with 

 two large and two small spines. The longer and' more slender of the former 

 at its proximal portion is bent rather abruptly at right angles to itself, but i3 

 nearly straight afterwards. The more robust is pretty straight, save at its dis- 

 tal extremity, where it is abruptly bent at right angles to itself. It is armed 

 with several very slender spinules, and has one edge distantly and obsoletely 

 denticulate. Of the smaller spines, one is short and blunt ; the other much 

 longer, sharp, slender and falciform. The last scutum is triangular, and has 

 its apex truncate and very slightly decurvate. The preanal scale is semi- 

 orbicular. 



Length, 2 to 3 inches. 



Hab. Mississippi. Museum of Smithsonian. 



Subgenus POLYDESMUS. 



P. HISPIDIPES. 



P. saturate olivaceo-brunneus, immaculatus; dorso nonnihil convexo ; scuto 

 anale triangulare longe pilose, apice truncato et decurvato ; pedibus hispidis ; 

 appendicibus masculis genitalibus brevibus, robustis, spina terminale modica, 

 ultima abrupte curvata, dense pilosa. 



The color is darker than in P. erythropygus. The side plates are rather 



1864.] 



