NORTH AMERICAN COLEOPTERA. 269 



SYSTEIVA Clark. 



Head inserted as far as the eyes, front witli very feeble frontal 

 carina and tubercles. Antennie slender, half as long as the body, 

 slightly thicker toward the tip, fourth joint longer than third or 

 fifth. Maxillary palpi comparatively slender, the last joint acumi- 

 nate and longer than the preceding. Prothorax transversely quad- 

 rangular, very little narrowed in front, margin very narrow, sides 

 feebly arcuate, anterior angles usually obliquely truncate, hind an- 

 gles acute, disc often broadly, but vaguely impressed in front of base ; 

 coxfe narrowly separated, the cavities closed behind, angulated ex- 

 ternally, the trochantin visible. Elytra usually wider at base than 

 the thorax, humeri obtuse. Legs rather slender, the posterior tibise 

 grooved on the outer edge and carinate, terminated by a single spur. 

 Claws appendiculate. 



The base of the thorax is usually feebly, regularly arcuate, occa- 

 sionally near the hind angles the base is slightly oblique as in Dis- 

 onycha. The ante-basal impression is vague at best, but many speci- 

 mens occur in every species in which it is entirely obliterated. 



In his generic description Chapuis states that the posterior tibi?e 

 are not grooved. Quite the contrary will be observed in our species. 

 There is not only a groove from the apex upward, but the edge of 

 the tibia forms a carina along the middle of this groove, especially' 

 observable in the larger species. In marginalis, however, the groove 

 is short and apical and in senilis it is entirely absent. The latter is 

 the only species in which there is an ante-basal impression, which is, 

 however, shallow and vague. 



The species occur in every part of our territoiy, each rather widely 

 spread. They are not numerous and easily known by the characters 

 of the following table : 



Elytra uniformly piceous or dark brown, slifthtly bronzed, or brijiht blue 2. 



Elytra vittate, or testaceous 7. 



2. — Legs piceous, or black 3. 



Legs rufotestaceous ; thorax reddish brown 6. 



3. --Thorax black 4. 



Thorax reddish yellow .5. 



4. — Head entirely black Iiliflsoiiias. 



Head rufotestsiceous frontalis. 



5. — Head black, elytra slightly bluish i'ollaris. 



(>. — Elytra brown bronze. 



Elytral punctuation sharply defined and closely placed Kliba^iiea. 



Elytral iiunctuation coarse and confused, not well defined |>allil>e!>t. 



Elytra bright blue; posterior tibije not at all grooved senilis. 



