218 COLEOPTERA OF NORTH AMERICA. 



Elasmocerus inhabits the Atlantic district, Cyniatodera is 

 widely diffused, the representatives of the other genera are 

 unknown to us Tillus collaris is found in Georgia, and 

 Periljpus is said to be from California. 



Group II. — Cleri. 



Head large, ej-es not very ])rominent, usually emarginate in 

 front; middle coxie ruunded, slightly i)rominent; tarsi with the 

 hi-st joint much shorter than the second, and covered by it, so as 

 not to be visible from above; the species are more numerous than 

 in the other groups. 



Eyes strongly granulated. 



Antennje serrate ; labial palpi alone dilated. Priocera. 



Anteimje with joints 9-11 longer. 



Last joint of labial palpi alone dilated. Opilus. 



Last joint of both paljii dilated. Tarsostenus. 



Eyes finely granulated. 



Last joint of both palpi broadly dilated. 



Antennae with abruptly formed, loose 3-jointed club. Aulicus. 



Antennae gradually broader to tip. Trogodendron. 



Last joint of labial palpi alone dilated. 



Last joint of maxillary palpi a little broader than the preceding joint. 

 Antennal club more or less triangular. Trichodes. 



Last joint of maxillary palpi slender. 



Eyes feebly convex, distinctly emarginate. 



Posterior tarsi rather broadly dilated. Clerus. 



Posterior tarsi slender and longer. Thanasimus. 



Eyes more convex, not emarginate. 



First joint of tai-si very short. Thaneroclerus. 



Trichodes, Clerus, and Thauasinins are widely extended, Auli- 

 cus and Trogodendron occur in California and Arizona; the other 

 genera are represented only in the Atlantic district. 



Clerononius is not sufficiently distinct from Thanasimus which 

 in turn seems hardly to differ from Clerus. 



Group III. — HydnocerL 



Head large, eyes very prominent, entire; middle coxoe not 

 prominent, slightly separated; tarsi with the first joint shorter 

 than the second, principally inferior; maxillary palpi cylindrical. 



But one genus of this group, Ilydnocera, exists in our fauna. 

 It is widely diffused ; the species are small, and have the form of 

 Cicindela; they are found on leaves of trees, and are active, taking 



