296 COLEOPTERA OF NORTH AMERICA. 



times wide and emarginate behind, sometimes triangular and 

 pointed, side pieces large; metasternum with side pieces wider 

 thau usual. Legs moderate in length, thighs generally strongly 

 clubbed, 1st joint of bind tarsi at least twice as long as the 2d. 

 Abdomen with ventral segments slightly diminishing in length, 

 5th, in % , short subemarginate. 



The antennae, in 1 , are usually longer than the body, and 

 thicker at base than in 9 • Flying hairs are seen on the legs and 

 antennae, and frequently on the body. 



As in the Stenopteri, there are mute and sonant genera, and 

 according to the sculpture of the mesonotum they may be arranged 

 as follows : — 



A. Mesonotum with a large, undivided, very finely striate stridulating 



surface. 

 Hind coxae not prominent, thighs slender. Gonocallus. 



Hind coxae very prominent, thighs strongly clubbed ; metasternum 

 with scent pores ; 

 Elytra with ivory lines. Physocnemum. 



Elytra uniform. Rhopalopds. 



Hind coxae not prominent ; metasternum without scent pores ; 



Prosternum broad or moderate, hind coxae inclosed by side 



pieces and 1st ventral segment. Hylotrupes. 



Prosternum very narrow, pointed, hind coxae not inclosed ; pro- 

 thorax rounded. Phymatodes. 



B. Mesonotum polished, with large scattered punctures ; 



Mesosternum broad, emarginate. Merium. 



Mesosternum obtusely triangular. Callididm. 



C. Mesonotum punctured and pubescent at the sides, with a medial stri- 



dulating surface. Xylocrius. 



Gonocallus is established on C. collare Kirby (lepidum Lee), 

 a very anomalous species with slender thighs, and the % antennas 

 12-jointed. It is an annectant branch towards Stenosphenus and 

 Clytus. 



Semanotus does not appear in the above scheme, as the former 

 representative of the genus in our fauna, G. ligneum Fabr., 

 appears to me more naturally placed as a section of Hylotrupes, 

 differing merely by the sternal pieces being less dilated. 



I have retained Merium Kirby, because the type M. Proteus, 

 though agreeing with Callidium in the sculpture of the mesonotum, 

 differs essentially in the form of the mesosternum ; the sculpture 



