82 Journal New York Entomological Society. [Voi. xxviii. 



carinatns, Iccontei, and Carahtis — vinctns and limhatus, the outer 

 part of the coxae is also flattened in part or wholly to the plane of 

 the metasternum and ventral segments; sometimes only the extreme 

 outer point as in the species of Cychrns and Carahus mentioned and 

 most of Pterostichus, or a half of the outward extension as in the 

 subgenus Poccilus of the genus Pterostichns, in the subgenera Amara 

 and Celia of the genus Amara, in the genera Loxandrus, Diplochila 

 and Diccelus; or the whole of the extension as in Chlccnhis. 



In general when the extension is flat, the outer part of the upper 

 plate is very narrow, the dividing groove then being close to the 

 metasternal suture. The extreme examples are found in the genera 

 CaUida, EiiprocHis, Pinacodcra and Onota, in which the extension 

 consists almost entirely of the lower plate. In these genera and 

 Chlcenius, therefore, is found the greatest dissimilarity in structure 

 and function between the two front pairs and the posterior pair of 

 coxae. 



Casnonia pcnnsylvanica and Casnonia hidoviciana show the great- 

 est dissimilarity in the structure of the posterior coxse to be found 

 in two closely related species. In the former the under plate is very 

 oblique and slightly flattened at the outer end, in the latter the under 

 plate is vertical and invisible from above. 



In the genus Plochionus the groove on the coxal extension is very 

 close to the anterior margin near the middle of the coxa, but curves 

 away from the margin at its outer extremity. This character is also 

 found in a greater degree in the genus Oodes. In Oodes amaroides, 

 amcricanus and fluviaUs the groove resembles that found in Plochio- 

 nus. In Oodes elegans the groove is sinuate; in cuprccus the groove 

 is in the form of a semicircle in its outer half; in quatuordecimsfri- 

 atns the semicircle occupies the whole of the coxal extension. No 

 known coxal structure could be represented by this groove, which, 

 therefore, seems to have lost its character as an indicator of struc- 

 ture and become merely sculptural ornamentation, a fact which de- 

 notes a remote ancestry for the genus. 



The trochanters of the anterior and intermediate legs like the 

 coxae are, with one known exception, invariable in form. They are 

 short, connate with the femur and joined obliquely with it, their 

 lower edge being prolonged. The apices are supported by short 

 prominences in the basal edge of the femur. The joint is nearly 

 rigid. 



