267 



The species are wideh^ distributed over the Athiutic slope, extend- 

 ing as far west as Utah {P. califoniicus) and Arizona (P. costifer 

 and mexicamis) ; none has occurred in Cahfornia, and the species 

 which bears the name of that region was certainly given to Baron 

 Chaudoir with an erroneous locality. 



The species may be divided into three groups, characterized as 

 follows : 



I. Elytra obtusely rounded behind ; spine of middle tibiae com- 

 pressed, obtuse at top. 



Elytra subacute behind ; spine of middle tibiae slender, acute ; 



II. Prothorax not constricted at base. 



III. Prothorax more or less constricted, hind angles prominent, 

 body more slender. 



I. SUBLAETIS Group. 



In this group the labrum is distinctly trilobed, the lateral lobes 

 wider than the middle one, and sinuate ; the mandibles are obliquely 

 rugose ; the mentum tooth rounded at tip, and scarcely concave. 

 The 2-4 joints of the antennae are not compressed. The prothorax 

 is strongly but narrowly margined, broadly rounded on the sides, 

 somewhat narrowed at base, but not constricted. The elytra are 

 parallel on the sides, convex, obtusely rounded behind, and more or 

 less sulcate; the humeral cai'ina fades gradually into a faint inter- 

 space between two of the furrows ; the general form is more robust 

 than in the other groups. 



1. P. strenuus, n. sp. 



Very large, protliorax rather suddenly narrowed at the base, hind angles 

 rectangular prominent ; elytra feebly sulcate. 



Length, db iw.m..; 1.4 inch. 



Two specimens, Florida. For a very fine specimen of this, the 

 largest species of the genus, I am indebted to Mr. P. S. Sprague, 

 and for another to Mr. Edward Tatnall, Jr. It is closely related to 

 the next, and with a large series of specimens will probably be 

 found to vary in a similar manner. It is easily knoAvn by the rec- 

 tangular hind angles of the prothorax. 



