158 COLEOPTERA OP NORTH AMERICA. 



Anterior and middle coxae small, rounded, not prominent, 

 without trochantins, the anterior ones received in cavities 

 formed by the pro- and mesosternum ; posterior coxae trans- 

 verse, contiguous, dilated into a plate partly covering the 

 thighs. 



Legs short, contractile; tibiae slender, with indistinct spurs; 

 tarsi short, 5-jointed, joints 1 — 4 furnished beneath with long 

 membranous lobes ; claws simple, onychium none. 



This family contains only a few small species belonging to two 

 genera, representing different tribes ; they are found on flowers, 

 and have been classed with Eucnemidaa by some recent authors, 

 although the totally different construction of the anterior coxal 

 cavities at once separates them. They do not possess the power 

 of leaping, like most species of the next family, and the fixity of 

 the prothorax on the trunk would show that any such act is me- 

 chanically impossible. 



Species of both genera are found on the Atlantic and Pacific 

 slopes. The tribes and genera are distinguished as follows : — 



Antennae terminated by a 3-jointed club. Throscus. 



Antennas serrate from the third joint outwards. Dkapetes. 



The name Trixagus Kugellann has priority over Throscus, but 

 being applied to a genus composed of the one now under con- 

 sideration and Byturus, it must be dropped for both. 



Fam. xxxv.— elaterid ae. 



Mentum small, corneous, quadrate, sometimes rounded in 

 front; ligula without paraglossae ; labial palpi 3-jointed. 



Maxillae exposed at the base, with two lobes, the outer one 

 sometimes very small ; palpi short, 4-jointed. 



Antennae inserted on the front in grooves, or under the 

 margin of the front, 11-jointed, rarely 12-jointed, more or less 

 serrate, sometimes flabellate or pectinate, the outer joints 

 rarely in the first sub-family enlarged, forming a serrate club. 



Head frequently retracted, sometimes advanced ; usually 

 applied to the prosternum beneath ; mandibles small, cor- 

 neous; labrum distinct in most species, indistinct in the first 

 and second sub-families. 



Prothorax with the side pieces not separate; coxal cavities 

 small, rounded, not closed behind by the mesosternum ; 



