PTEROSTICHIISLE 319 



Subfamily PTEROSTICHIN^E 



This is one of the largest of the Carabid subfamilies, and so far 

 as generic subdivision is concerned, perhaps the most difficult. In 

 the definition of genera, more consideration should be given to gen- 

 eral habitus than to many of those modifications of special organs 

 constituting the so-called structural characters considered essential 

 by many authors. There are some of these structural modifica- 

 tions of special organs, such as the very singular hind tarsi of Ham- 

 matomerus, the simply rounded mental tooth of Piesmus, as re- 

 corded by LeConte, and the numerous broadly impressed elytral 

 fovese of Bothriopterus, which, though unaccompanied by habital 

 differences of marked degree, would nevertheless seem to indicate 

 of themselves distinct genera, but as a rule restricted structural 

 characters are not so decisive as marked difference of habitus, 

 which for instance, forms the chief point of distinction between 

 Holciophorus and Hypherpes. One could not hesitate at all in de- 

 ciding that Holciophorus is a different genus from Hypherpes at a 

 mere glance. In the vigorous search for special structural charac- 

 ters to supplement obvious habital differences, many misconcep- 

 tions have occurred and modifications of really slight importance 

 used in the separation of groups remarkably similar in general ap- 

 pearance, such for instance as the presence or absence of external 

 striation on the tarsal joints. LeConte separates Evarthrus because 

 of the broader and widely truncate fourth palpal joint being shorter 

 than the third, overlooking the fact that this is almost the identical 

 structure of the palpi in the widely different Holciophorus and occurs 

 to some extent in several other groups as well as Evarthrus. In 

 fact the subfamily Pterostichinse constitutes one of those composite 

 aggregates, wherein the division into surnamed units for taxonomic 

 convenience should be founded more upon sense of proportion than 

 upon differences of structure in special organs. 



In applying definite tangible structural peculiarities to the def- 

 inition of generic groups, a few observations seem appropriate. 

 First, the form of the basal angles of the prothorax is not decisive 

 in the limitation of genera; there are four or five groups to be re- 

 called at present where the form of these angles varies from acutely 



