AMERICAN COLEOPTERA. 99 



similar to that to which I have already called attention in some 

 Tachyporini, but still more strongly marked. In Helodes and Scirtes 

 (except one species), this ridge is absent. 



So'rtcs is remarkable for the dilated hind femora giving the species 

 a saltatorial power. In some Helodea the femora are somewhat thick- 

 ened and approach the structure of Scirtes. 



The genera have had but one addition since the publication of the 

 "Classification," namely, Microcara, the validity of which is denied 

 by some authors, but its characters give it more claim to be separated 

 from Helodes than do those of Prinnocyphon. 



Our genera are separated in the following manner : 



Third joint of labial palpi arising from the side of the second. (PL I, fig. 17). 

 Posterior femora normal, tibial spurs moderate. 



First joint of antennae expanded, posterior tarsi flat above and bicarinate. 



(PI. I, fig. 12) Prionocyphon. 



First joint of antennae not expanded. 



Posterior tarsi convex above, not carinate, the third joint normally 



visible iVIieroeara. 



Posterior tarsi flat and bicarinate above, the third joint in great part 

 concealed by the prolongation of the upper edge of second joint. 



(PI. I, fig. 14) Helodes. 



Posterior femora broad, saltatorial, the spurs of posterior tibiae long. 



(PI. I, fig. 15) Scirtes. 



Third joint of labial palpi arising from the end of the second. Tarsi convex 

 above not carinate Cyphon. 



The above genera are all represented in the Atlantic region, 

 Cyphon and Helodes alone in the Pacific, although Motschulsky 

 describes one Scirtes from California. Helodes as above defined 

 includes Sacodes Lee. 



PRIONOCYPHON Hedt. 

 Head deflexed, front without suture, a well defined subocular ridge. 

 Eyes round, moderately prominent. Antennae slender, longer than 

 half the body, first joint oval, explanate in front, second and third 

 joints very small, the latter especially so, fourth joint a little shorter 

 than the first, fifth a little shorter than fourth, 6 — 11 subequal, similar 

 to the fourth, in the male of one species a double row of appendages 

 arises from the base of joints 4 — 10. Mentum nearly square, ligula 

 transverse, emarginate in front, the angles rounded. Labial palpi 

 with second joint long, the third arising at a right angle from its 

 middle. Maxillary palpi longer, last joint oval, subacute at tip. Pro- 

 sternum in front of coxa; very short, prolonged in a slender plate 

 between and extending behind them (the tip is variable in the two 



