eucnemim:. 211 



In order that the genera at present known in the Central American fauna may be 

 determined, the following table has been prepared. As it represents but a third of 

 the known genera of the family it has been possible to avoid some of the more difficult- 

 to-realize characters used by de Bonvouloir. 



1. Posterior coxae deeply inserted in their cavities, without coxal 



plates . Cerophytum. 



Posterior coxse with distinct plates, which more or less cover the 

 femora in repose 2. 



2. Marginal carina of the pronotum parallel with the prosternal 



sutures. 



Legs and tarsi stout and broad Melasis. 



Legs and tarsi slender Isorhipis. 



Marginal carina and prosternal sutures convergent in front ... 3. 



3. Abdomen with longitudinal grooves for the reception of the 



posterior tarsi Gastraulacus. ■. 



Abdomen not grooved 4. 



4. Prosternal sutures excavated to form the antennal cavities . . . 28. 

 Prosternal sutures not excavated ; but there may be a juxta- 



sutural sulcus 5. 



5. Posterior coxal plates dilated internally, or when parallel (Micro- 



rhagus) the thorax has supplementary carinse 6. 



Posterior coxal plates broad and nearly parallel ; thoracic margin 



simple; a marginal sulcus 21. 



6. Propleurse with marginal antennal groove 7. 



Propleurse without marginal groove 16. 



7. Metasternum with a distinct longitudinal groove beginning at the 



outer end of the middle coxal cavities 8. 



Metasternum without an impressed line 9. 



8. Metasternum with a short oblique elevated line beginning at the 



anterior outer angle Pcecilochrus. 



Metasternum without oblique elevated line in front Idiotarsus. 



9. Marginal groove continued on the head without being narrowed by 



the eyes 10. 



Marginal groove much narrowed by the eyes 13. 



10. Antennal groove sharply limited on the inner side ; last ventral 



segment not prolonged in a point 11. 



Antennal groove not sharply limited on the inner side ; antennas 



broadened and flat ; last ventral segment prolonged in a point . Eurachis. 



11. Marginal groove at least wider than half the propleural triangle. 



Groove wider in front; fourth tarsal joiat excavate- 



emarginate Phanobolus. s 



Groove much wider behind ; fourth tarsal joint simple . . Deltometopus. • 



Marginal groove narrower than half the propleural triangle . . 12. 



2E2 



