168 COLEOPTERA OF NORTH AMERICA. 



AlDclomen with five free segments, the fifth rounded at tip. 



Anterior coxa3 transverse, frequently prominent; in the 

 first sub-family, with large trochantin, in the second with- 

 out; middle coxas smaller, sub-transverse, rarely with, usu- 

 ally without, trochantin; posterior coii.se transverse, nearly 

 contiguous, dilated into a plate partly covering the thighs. 



Legs short, tibiae slender, with small, and sometimes obso- 

 lete terminal spurs; tarsi 5-jointed, frequently with mem- 

 branous lobes beneath ; claws simple or pectinate ; onychium 

 (in some genera) very short, with two terminal bristles, 

 sometimes wanting. 



A family wliich, although of small size, contains genera widely 

 differing in many of their characters ; they all live on plants 

 usually near water. 



They naturally divide into two sub-families : — 



Anterior coxje with distinct trochantin. Dascyllin^e. 



Anterior coxae without trochantin. Helodin^. 



Sub-Family I.— DASCYLLIN.^. 



The anterior coxjb are transverse, rarely more prominent than 

 the prosternal process which moderately separates them. The 

 trochantin is large and very distinct. The mandibles are always 

 more evident than in the second sub-family. The tibias are never 

 bicarinate externally and the spurs comparatively small. The 

 claws are simple or feebly dilated at base, pectinate in Odontonyx. 



Three tribes are indicated by the genera iu our fauna distin- 

 guished in the following manner : — 



Antennae distant at base, front not narrowed ; 



Epistoma prolonged, concealing the labrum in great part and the man- 

 dibles, posterior coxae narrowly separated. Macropogonini. 

 Epistoma short, labrum and mandibles visible, posterior coxae contigu- 

 ous. Dascyllini. 

 Antenn.-e apijroximate at base, front narrowed ; 



Labrum visible, mandibles short, mouth inferior. Brachypsectrini. 



The trochanters of the anterior and middle legs are elongate 

 in the first tribe, short in the second and third. 



Tril)e I.— MACROPOGOXIIVI. 



Head free, slightly deflexed, received in the thorax as far as 

 the eyes, clypeal suture obliterated, front slightly prolonged in 



