160 PROCEEDINGS OF THE NATIONAL MV8EVM. vol.42. 



Key to genera of subtribe Tylodina. 



Metepisterna very small, usually invisible, not fused with metasternum. 



1. Scutellum invisible. 



a^. Elytra without humeri; antennal funicle 7-jointed. 

 6'. Second ventral segment at least as long as the third and fourth together. 

 c^ Second ventral segment considerably longer than third and fourth together; 

 femora mutic; eyes separated by at least the width of the beak; vesti- 

 ture spongy; pro thorax prolonged over head; ocular lobes very promi- 

 nent, covering eyes (type, L. solitarius Boheman). . Lembodes Schonherr. 

 (?. Second ventral segment not much longer than the third and fourth 

 together; femora mutic; eyes separated by the width of the beak (type, 



T. armadillo Sahlberg) Tylodes Schonherr. 



6^. Second ventral segment not as long as the third and fourth together. 



rf*. Second ventral segment much longer than either the third or fourth; 

 tarsal claws very small, approximate. 

 e^. Antennal club annulated only near tip; first abdominal segment with 

 deep, polished triangular impression; tibiae straight; intercoxal 

 process of abdomen triangular (type, E. pyriformis LeConte). 



Eurhoptus LeConte. 



c^. Antennal club annulated; elytra 9-striate; first abdominal segment 



squarely truncate behind; at least front tibiae bisinuate within; 



eyes separated at least by width of beak; intercoxal process truncate; 



scales intermixed with bristles (type, A. camelus Fabricius). 



Acalles Schonherr. 



cP. Second and third ventral segments subequal; femora unarmed; eyes 



rounded above, acute beneath, closer together than width of beak; 



scrobes directed at lower corners of eyes; scales not intermixed with 



bristles (type, G. bifasciata Gerstaecker) Gerstaeckeria Champion. 



a^. Elytra with rectangular humeri; funicle 7-jointed. 



^^ Eyes separated by width of beak; femora dentate; scales inter- 

 mixed with bristles; second ventral segment longer than either 

 the third or fourth (type, E. porcellus Boheman). 



Euscepes Schonherr, 



/2. Eyes separated by less than width of beak; femora usually dentate; 



ventral segments 2^ subequal; elytral vestiture not mixed with 



erect setae; scutellum sometimes visible (type, P. bicristatus 



Champion) Pseudomopsis ChamY)ion. 



2. Scutellum visible; funicle 7-jointed; ventral segments 2-4 subequal; elytra 



10-striate; femora mutic; claws divergent; humeri absent (type, P. notatus 

 Schonherr) Pseudomus Schonherr. 



Genus GERST^^CKERIA Champion. 



All of the cactus weevils at present known belong to this genus. 

 The type is Acalles hifasciatus Gerstsecker. A close study of the 

 material in the United States National Museum leads the writer to 

 divide the genus into four subgenera or species groups. 



Key to subgenera. 



1. Elytra with a post-humeral prominence; eyes well separated ; femora unarmed. 

 aK Antennae inserted toward the apex of the beak (type, X. inflata Champion). 



Xenosomina, new subgenus. 



a^. Antennse inserted at middle of beak; scrobes directed beneath beak; scape 



short, not reaching eyes; tarsal claws minute, parallel (type, 0. hubbardi 



LeConte"*. Opuntiaphila, new subgenus. 



