114 COLEOPTERA OF NORTH AMERICA. 



Fam. XXIX.— P A R N I D A E . 



Mentum corneous, trapezoidal, or emarginate in front; 

 ligula large, not lobed. 



Maxillae exposed at the base, with two unarmed lobes. 



Antennas variable in form and position. 



Head usually retractile; labrum distinct; mandibles small ; 

 eyes rounded. 



Prothorax with the side pieces not separate; coxal cavities 

 widely open behind, completed by the mesosternum, variable 

 in form; presternum prolonged behind the coxae. 



Mesosternum sometimes excavated, sometimes emarginate; 

 side pieces attaining the coxae. 



Metasternum with side pieces wide or narrow; epimera 

 (except in Psephenus) not visible. 



Elytra entire; epipleuras narrow, sometimes extending to 

 the apex. 



Abdomen with five, in Psephenus with seven ventral seg- 

 ments, the anterior ones connate. 



Anterior coxaa transverse, with large trochantin, or rounded, 

 without trochantin; micluie coxae oval, not contiguous; pos- 

 terior coxae transverse, dilated into a plate partly protecting 

 the thighs, and contiguous Vu the nl^t and second sub-fami- 

 lies; distant and not forming a plate in Elmiclse. 



Legs slender, usually king ; tibiae without distinct terminal 

 spurs; tarsi 5 jointed, joints 1—4 short, equal, fifth longer 

 than the others conjoined, large, with large simple claws. 



A family containing three very distinct sub-families, and show- 

 ing very diverse affinities not only with the preceding and following 

 families, but also, by the form of the antenna? of various members, 

 with the Gyrinidpje, and with some families of the Serricorn series, 

 especially the Helodidaa and Dascyllidge; a more distant rela- 

 tionship with che Donacia tribe of the Chrysomelidae, by the form 

 of the tarsi of Hsemonia, has also been pointed out by Lacordaire. 



Abdomen with seven ventral segments ; anterior coxse with very large tro- 

 chantin. PsEPHENIDiE. 



Abdomen with five ventral segments ; 



Anterior coxa? transverse, with distinct trochantin. Paenidae. 



Anterior coxae rounded, without trochantin. Elmicb. 



