156 MEMOIRS ON THE COLEOPTERA 



Calathus Bon. 



This genus, together with Pristonychus and Pristodactyla, is well 

 distinguished from the other allies of Platynus by the serrulate or 

 pectinate tarsal claws. In Calathus they are rather pectinate than 

 serrulate, this condition obtaining more especially in Pristonychus, 

 where the claws are much more feebly modified. The Atlantic 

 coast and Sonoran species of Calathus, as distinguished from the 

 purely Pacific coast types, are numerous and may be distinguished 

 among themselves as follows: 



Prothorax distinctly reflexed at the sides 2 



Prothorax flatter, scarcely at all reflexed at the sides or only very narrowly 

 and feebly so toward base; surface shining, the micro-reticulation 

 hexagonal as in gregarius 7 



2 Elytra strongly shining in both sexes, elongate-oval, black or feebly 

 picescent, the thoracic sides, legs and antennae testaceous; surface 

 smooth and polished; prothorax subquadrate, feebly rounded at the 

 sides and slightly narrowed at apex, fully four-fifths as wide as the 

 elytra, the latter elongate-oval, with broadly rounded sides and 

 without exposed humeri; male a little more slender than the female; 

 micro-reticulation hexagonal. Length 8.0-10.0 mm.; width 2.9-3.8 

 mm. New Hampshire to Missouri gregarius Say 



Elytra opaque or strongly alutaceous, apparently in both sexes but 

 always in the female; micro-reticulation compressed, rhomboidal. .3 



3 Sides of the prothorax parallel, broadly, feebly and almost evenly 

 arcuate from base to apex, only very slightly more converging 

 apically than basally. Body elongate-oval, rather narrow and sub- 

 depressed, castaneous, the thoracic sides, legs, scutellum and antennae 

 testaceous; head dark testaceous; prothorax quadrate, the basal 

 angles right but broadly rounded; surface with obsolescent rugulae 

 radiating from the median stria; elytra oblong-oval, with feebly 

 rounded sides, almost a fourth wider than the prothorax, having 

 very fine and feebly impressed striae and almost flat intervals; side 

 margins pale and distinctly reflexed; head a little more than half 

 as wide as the prothorax; hind tarsi about as long as the tibiae, the 

 claws rather longer and straighter than usual, more abruptly hooked 

 at apex. Length (cf) 8.5 mm.; width 3.1 mm. Arizona. 



sonoricus n. sp. 



Sides of the prothorax more rounded and much more convergent apically. 4 



4 Elytra rather shining though with an alutaceous lustre; body small, 

 narrow, the hind tarsi (cf ) very slender and rather shorter than the 

 tibiae. Piceous-black, the margins, legs and antennae as usual; 

 head small, only about half as wide as the prothorax, which is not 

 quite as long as wide, otherwise nearly as in opaculus, the elytra 

 relatively narrower, of the usual form, the side margins perhaps 

 slightly more narrowly reflexed, the micro-reticulations strong, 

 rhombiform, not quite so fine but especially not so laterally com- 



