4 
NORTH AMERICAN THROSCIDAE 
a longitudinal internal carina nearly or quite to the apex, 
against which rests the acute margin of the abdomen. In the 
only Lissomus I have been able to examine the elytra are free at 
apex, as in most Elaterinae. 
The tribes and genera of Throscinae separate as follows: 
Anterior and middle trochanters long; prosternum lobed in front. 
LISSOMINI 
Anterior and middle trochanters short; prosternum truncate in front. 
THROSCINI 
LISSOMINI 
Claws toothed at base; metasternum with oblique impressed line; pygidium 
projecting slightly beyond the elytra Drapetes 
THROSCINI 
Antennae fusiform ; tarsi simple Pactopus 
Antennae clavate; tarsi with fourth joint bilobed. 
Metasternum with long oblique groove for the reception of the middle 
tarsi Aulonothroscus 
Metasternum with tarsal grooves very short and only feebly diverging from 
femoral sulcus Throscus 
LISSOMINI 
This tribe is chiefly tropical, only two species of Drapetes being 
in the European catalogues and five in our own fauna. The 
species, as a rule, are larger with a more or less polished surface 
and with a more varied coloring than in the Throscini. The 
mandibles are bifid, the prosternum is strongly lobed, the ante- 
rior and middle trochanters are slender and elongate, and the 
antennae are serrate or even pectinate from the fourth to the 
tenth joints, and in repose rest not in well defined sulci, but in 
pockets or enclosed cavities in the anterior part of the flanks of 
the prothorax, reaching quite to the side margin under the sides 
of the pronoturn, the openings being along the anterior part of 
the prosternal sutures. The antennae when withdrawn are in 
the form of a loop, the terminal joints frequently visible in the 
opening and pointing forward. In one specimen of D. rubricollis 
the pronoturn was so translucent that the antennae could be 
seen beneath at the sides. In Drapetes the mesosternum has a 
striking lobe to engage the prosternal spine, horizontal and much 
as in ordinary Elaterinae, while in the Melasinae (Eucneminae) 
