428 COLEOPTEKA OF NORTH AMERICA. 



This family contains a few species inhabiting the northern 

 temperate zone, and depreciating on the male flowers of conifer- 

 ous trees ; in which the eggs are deposited. As has been 

 observed on a former occasion, this family is a synthetic or un- 

 differentiated type in which the Rhynchophora make the nearest 

 approach to the lower Heteromera ; it is therefore interesting to 

 see that it clings to a very ancient and synthetic type of vegeta- 

 tion. 



Our species belong to two genera. 



Beak flattened, broader in front of the antennae. Rhinomacer. 



Beak cylindrical. Diodyrhynchus. 



The first genus is represented by species on each side of the 

 continent; the second by one species in jS'evada and California. 



Fam. LXXV.— rhynchitidae. 



Mentura small, subquaclrate, supported upon a long nar- 

 row gular peduncle; ligula prominent, small, palpi sliort. 



Maxilla3 exposed, palpi short, rigid, as in Curculionidte, 

 4-jointed. 



Mandibles toothed on the outer and inner side ; capable 

 of great lateral extension; in repose the outer apical tooth 

 on each projects forwards, so that two small acute teeth 

 seem to project from the mouth. 



Antenn£B inserted at the sides of the beak,. in position 

 varying according to the genus; 11-jointed straight, first 

 joint not elongated, and scarcely stouter, 2-8 slender, 9-11 

 broader, forming a loose club, and covered with sensitive 

 surface. 



Head prominent, not deflexed, eyes rounded finely granu- 

 lated; beak slender, varying somewhat inform according 

 to the genus. 



Prothorax truncate before and behind, convex, prosternal 

 sutures not visible, coxal cavities rounded, somewhat trans- 

 verse, with a distinct fissure at the outer side margin: dis- 

 tant in Pterocolus, confluent in other genera. 



Mesosternura flat, acute behind in all but Pterocolus, and 

 with the side pieces normal in form and diagonally divided; 

 in that genus they are transverse, prominent, apparently 

 undivided, and ascend between the prothorax and humeral 

 angle of the elytra, suddenly declivous and excavated in 



