178 C0LE0PTERA OF NORTH AMERICA. 



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

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

 ally near water. 



They naturally divide into two sub-families : — 



Anterior coxae with distinct trochantin. Dascyllid^e. 



Anterior coxae without trochantin. Helodid-s:. 



Sub-Family I.— DASCYLLIDAE (genuini). 



The presence of an anterior trochantin will readily distinguish 

 the genera of this sub-family, the species of which are of larger 

 size than those of the following sub-family. The anterior coxae 

 are very transverse, rarely prominent. The prosternum is always 

 cpiite well developed in front of the coxa?, and is usually visible 

 between them. The spurs of the tibiae are distinct. 



The genera may be arranged in tribes as follows : — 



Prosternum prolonged, entering the mesosternum. Mackopogonini. 



Prosternum not prolonged. Dascyllini. 



Tribe I.— MACROPOGONINI. 



The head is convex, without clypeal suture ; the antenna? are 

 scarcely serrate ; the prosternum is flat, with distinct side mar- 

 gins converging behind ; the mesosternum is emarginate and re- 

 ceives the tip of the prosternum ; the plates of the hind coxa? are 

 very narrow ; the second and third joints of the tarsi are slightly 

 lobed beneath, and the fourth joint has two long narrow lobes; 

 the claws are simple, and the onychium is wanting. 



Two genera are recognized by Motschulsky. 



Antennae with the second and third joints small. Eprypogon. 



Antennae with the second, third, and fourth joints small. Macropogon. 



Eunjpogon nigra (Ochina nigra Mels.) is the only species of 

 the genus known ; it is found in the Atlantic States on plants. 

 Macropogon occurs in California and Oregon. 



Motschulsky has placed these genera in Elateridae, from which 

 the large trochantins and different form of the anterior coxae at 

 once distinguish them. 



