ANTHRIBIDAE. 52T 



Tribe I.— TROPIDERIIVI. 



The genera of this tribe are sufficiently distinguished by the 

 position and form of the prothoracic ridge, whicli is remote from 

 the base, more or less sinuous, and flexed obliquely at the sides. 

 The antennae are situated under the lateral edge of the beak, 

 which is sometimes flattened and expanded so that the antennal 

 cavities are partially covered. 



Three groups occur in our fauna : — 



Eyes entire, suture of mentiim obliterated. 2. 



Eyes emarginate ; suture of mentum distinct. Hormisci. 



2. Sides of beak not dilated; antenn?e very long. Ischnoceri. 



Sides of beak dilated over tbc antennal cavities. Tropideres. 



Group I. — Ischnoceri. 



Beak longer than the head, dilated at tip ; antennal cavities 

 large, lateral, limited above by a small, elevated line, which de- 

 scends to the inferior margin of the eyes. Eyes longitudinal, 

 elliptical, rather coarsely granulated. Antennae very slender, 

 longer than the body in %; two-thirds as long in 9; first joint 

 very short; second twice as long as first, and more than one-half 

 as long as third; 9-11 broader, forming a compressed, loose, 

 oval club. Tarsi with the first joint long ; second triangular, 

 emarginate, with prolonged angles ; third as wide as the second, 

 bilobed ; claws armed with a long, acute tooth at the middle. 



One species of Ischnocerus extends from Mexico into the 

 Southern States. 



Group II. — Tropideres. 



The sides of the beak in the insects of this group are dilated 

 over the antennal cavities, which are therefore not visible from 

 above. The form of the antebasal ridge differs in each genus, 

 and in conjunction with the antennal club and tarsal claws affords 

 easy characters for distinguishing the genera. The eyes are 

 entire, either rounded or oblique. 



Antennal club narrow, not compressed. 2. 



Antennal club oval, compressed. 3. 



2. Protlioracic ridge strongly angulati'd and toucbing tbe base at tbe 



middle ; claws simple. Gonotropis. 



Protlioracic ridge straiglit at tb(! middle, base deeply biemarginatc ; 



claws acutely tootbed. Eurymycter. 



3. Eyes oblique, sligbtly oval, beak sbort. Tropideres. 

 Eyes rounded, beak longer, antenna; % very long. Allandrus. 



