405 



is no scutellar stria, the first ending at base in a large dilatation, 

 which includes the minute elevated subscutellar tubercle not a 

 puncture in this case or in Trechus. This unusual disposition of 

 the basal part of the first stria and the scutellar stria, is very differ- 

 ent from that characterizing the Pterostichinae, where the scutellar 

 stria lies between the first and second striae and proceeds directly 

 from the ocellate puncture, but I have noted in some Evarthrids, 

 as an abnormal feature, that the first stria may be deflected at 

 base, becoming coincident with the scutellar stria and ending in 

 the puncture, the true base of the first stria being disconnected and 

 free. By evolution this detached basal part of the first stria, has 

 become the regular scutellar stria in the Pogonid genera, the first 

 regular stria being always and normally deflected outwardly at base 

 to the ocellate puncture. 



Trechus Clairv. 



This genus of comparatively minute species when compared 

 with the preceding genera, together with Anophthalmus, differs very 

 greatly from the preceding types in having the hind body narrowly 

 pedunculate and in having the fourth palpal joint slender, acicu- 

 late and frequently longer than the third, though in Anatrechus, 

 defined below, the maxillary palpi are much thicker than in Trechus, 

 approaching the structure seen in Patrobus. In Trechus the frontal 

 sulci are usually more prolonged and outwardly curvate posteriorly 

 than in Patrobus. The elytra are nearly similar in general structure, 

 except that there is at apex a coarse deep arcuate prolongation of 

 the fine fifth stria, which is absent in Patrobus and related genera. 

 The legs and trochanters are unmodified as in Patrobus, but the 

 general structure of the under surface is similar. There is a single 

 puncture at each side of the abdominal tip in both sexes and the 

 posterior of the three dorsal punctures of the elytra is very near 

 the apex. 



Trechus and Anophthalmus are both enormously developed in the 

 European fauna, but they are comparatively poor in species and 

 rare in individuals in North America. Our very moderate number 

 of Trechus species may be known as follows: 



Outline more nearly parallel, the hind body oblong-suboval 2 



Outline strongly ventricose, the hind body more inflated and ovulate. .8 

 2 Eyes rather large and prominent. Pacific coast fauna 3 



