BEETLES. 



399 



FIG. 495. Metrius contrac- 

 tus, enlarged. 



FIG. 496. Elaphrus riparvus. 



Metrius contractus, from California, is the single species representing a tribe which 

 differs from Scarites in having the body not pedunculate and the posterior coxae sepa- 

 rated. This beetle is found under stones in forests. 



The genus Elaphrus differs from the genera of Carabinae 

 already mentioned in having the antennae free at the base. In 

 this genus the form is robust, the mandibles have a setigerous 

 puncture, and the elytra are marked with impressed spots. The 

 species of this genus are found running about in the sunlight on 



the surface of the mud around the 



borders of ponds and pools. The 



color of many of the species is a 



purplish or greenish bronze. E. ri- 



parins, which is figured, is about 



0.25 of an inch long, and is com- 



mon in parts of Europe. In Ble- 



thisa the elytra have striaa between the impressed spots. 



7?. multipunctata is a European species that has been 

 found in America. According to Laudoit, E. riparius and JB. multipunctata stridulate 

 by rubbing the upper side of the penultimate abdominal segment 

 against the inside of the elytra, both the parts rubbed together being 

 provided with surfaces suitable for sonifaction. 



The typical genus of this family is Cardbus, which is represented in 

 North America by only about ten species, reaches its highest develop- 

 ment in Europe, where a large number of species are found. In this f /WjNjff^ \ 

 genus the anterior coxal cavities are open behind, the posterior coxa3 

 are contiguous, the labrurn not bifurcate, the mandibles without a 

 setigerous puncture externally, and the third ioint of the antennae 



. . . . p 



cylindrical. Most of the species are of medium, some of large size, 



and many have beautiful coloration. Their food consists of earth- 

 worms, caterpillars, and other insects. The species of Carabus, and 

 those of the allied genera Calosoma and Cychms, have well-devel- 

 oped anal glands, and throw a strong acid fluid. C. serratus is the 

 most abundant species in the northeastern United States. It is from 

 0.60 to 0.75 of an inch long, is black, with the upturned margins of 

 the prothorax and elytra bluish, and its elytra are punctate. C. 

 sylvosus, from the same region, is similar to C. serratus, but larger, 

 being about an inch long. One of the prettiest of the common 

 European species is C. auratus, which is nearly an inch in length, 

 and has the entire upper surface greenish bronze with a reddish re- 

 flection. In C. glabeattis, another European species, the elytra, which, are often con- 

 nate in this genus, are so firmly united that the suture between them is scarcely 

 noticeable. C. hispanus, from Spain and southern France, is about 1.4 inches long; 

 and the elytra are coarsely punctured, and reddish bronze margined with blue, while 

 the head and the prothorax are metallic blue. Procrustes differs but little from 

 Carabus. P. coriaceus, a black species, nearly 1.5 inches long, is found throughout 

 southern Europe. 



Calosoma differs generically from Carabus in having the third antennal joint 

 compressed. The habits of the species of this genus are very similar to those of 



multipunctata. 



FlG. 498. Carabus 

 serratus. 



