174 COLEOPTERA OF NORTH AMERICA. 



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



visible. Microcara. 



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



part concealed by the prolongation of the upper edge of second 



joint. Helodes. 



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



Scirtes. 

 Third joint of labial palpi arising from the end of the second. T.-irsi con- 

 vex above, not carinate. Cyphon. 



In Helodes the hind coxae are suddenly dilated internally, and 

 in our species, the head is covered by the thorax, which is rounded 

 in front; these species form Sacodes Lee, which has been 

 suppressed. In Prionocyphon and Cyphon the hind coxa3 are 

 strongly but gradually dilated internally. Scirtes, Cyphon, and 

 Helodes occur on both sides of the continent; the other two 

 genera thus far only on the Atlantic slope. 



Tribe V.— PL,ACO]V¥CHI]VI. 



Front narrow, antennge closely inserted. Anterior coxob with- 

 out trochantiii. Tarsi slender, claws with slender membranous 

 lobes arising from the base. 



In these few words a tribe is defined containing a single 

 species possessing the oral organs of the Eubriini, a prosternum 

 approaching the Helodini with a structure of tarsal claw entirely 

 unique in the family. 



This tribe contains but one genus Placonycha with the follow- 

 ing characters : — 



Head as in Ectopria. Eyes equal in the two sexes. Antennge 

 pectinate % , serrate 9, very like Ectopria. Ligula with four 

 processes, shorter and less slender than in that genus. Palpi 

 similar to Ectopria. Prosternum short in front of the coxse. 

 prolonged narrowly between them and not elevated. Anterior 

 coxa3 moderately prominent, higher than the prosternum and 

 without trochantin. Mesosternnm of moderate width, depressed 

 and oblique. Posterior coxas suddenly but moderately dilated 

 internally and contiguous, very narrow externally. Legs as in 

 Ectopria. Tarsi slender, not lobed nor dilated, joints 1-4 gradu- 

 ally decreasing in length, fifth a little longer than the first and 

 with a distinct bisetose onychium. Claws slender and simple at 

 tip, moderately dilated at base, and with a slender membranous 

 appendage arising from the base nearly as long as the claw. 



