CARABIDAE. 39 



the Inst two joints nearly equal, the terminal slightly fusiform, 

 acute at tip. Mcntuin eniarginate and toothed, ligula usually 

 truncate at tip and bisetose, the a})cx free for a short distance, 

 the i)arag-Ioss3e sniali, rather longer than it, the palpi slender, tlie 

 last joint slightly fusiform, acute at tip, the penultimate not 

 longer than it, and bi-, rarely trisetose in front. Thorax narrow, 

 the margin usually feeble or even entirely obliterated, a seta near 

 the middle of the side, a second at the hind angle which is often 

 feeble. Body subpedunculate, scutellura not projecting between 

 the eh^tra. Elytra oblong-oval, base not margined, sides nar- 

 rowly inflexed, margin entire without internal plica, the apices 

 truncate, sometimes rather obliquely. Prosternum not prolonged. 

 Mesosternum oblique, the epimera very narrow. Metasternal 

 epimera distinct, posterior coxee contiguous. Legs slender, the 

 middle and posterior tibiae slightly ciliate externally, the anterior 

 emarginate within, the spurs. small. Tarsi usually slender, rarely 

 flattened, the fourth joint at most feebly emarginate. Claws 

 simple. 



The anterior tarsi exhibit no differences in the two sexes. 



In all the genera there will be observed numerous punctures, 

 bearing short erect hairs, situated either iu the second stria or 

 the third interval. 



There is a close relationship between this tribe and the Cteno- 

 dactylini, aud they are united by some authors, the only difference 

 of moment being that the elytra are here truncate and there 

 entire. 



With the Lebiini and Dryptini there is also a very close re- 

 lationship. 



No constant character seems to separate the Odacanthini from 

 the Dryptini except the form of the labial palpi. 



The only genus which occurs in our fauna is Casnonin, repre- 

 sented by two species pennsi/lvanica and ludoiriciana, in which 

 the setigerous punctures of the second stria are very indistinct, 

 and rarely more than four in number. The last-mentioned spe- 

 cies is remarkable in having the thoracic margin rounded and the 

 sutures of the under side entirely ol)literated. The only other 

 instance known of such a structure is in Apotomus, which 8chaum 

 says is distinguished from all other Carabida^ in this manner. 



