108 AMERICAN ENTOMOLOGY. 



elytra dark bluisli-green, or somewhat violaceous ; middle of the 

 lateral edge obsoletely piceous : postpectus and feet deep black : 

 \"enter testaceous. 



Variety, a. Elytra blue ; venter and thorax sanguineous. 



Ohs. This species was taken on the Mississippi, and specimens 

 also occurred near the Rocky Mountains. It is as large as M. 

 AL-maculatus Fabr., and larger than M. thoracicus Fabr., which 

 it much resembles. The variety was sent me from Massachu- 

 setts by Mr. Charles Pickering. 



The right figui'e of the plate. 



[Also a Colhps. — Lec] 



Malachius nigriceps. — specific character. Thorax rufous, 

 with a large black spot : elytra blue : venter sanguineous. 



M. nigriceps nobis. Jour. Acad. Nat. Sci. vol. iii. p. 183. 



Desc. Head deep black, pale testaceous or rufous before : tho- 

 rax rufous, with a large black spot, sometimes composed of two 

 dilated, confluent ones, and not attaining the anterior margin : 

 elytra violaceous, blue, or greenish ; pectus rufous, at the origin 

 of the feet black : postpectus black : feet black : thighs sometimes 

 rufous, particularly the anterior ones : venter sanguineous. 



Variety, a. Thorax entirely black. 



Ohs. Distinguishable from the tricolor by the black spot of 

 the thorax, and by the proportion of this part, which is compa- 

 ratively longer than in that insect. Its antenuse present the re- 

 markable character of the dilatation and irregularity of the 

 second joint of the antennre. 



The upper middle figure of the plate. 



[Also a CoUops ; the form of the second joint of the antennas 

 mentioned is peculiar to the male. — Lec] 



Malachius vittatus. — Sjyecific character. Thorax rufous, 

 with a large black spot : elytra blue, margin and suture rufous. 



M. vittatus nobis, Jour. Acad. Nat. Sci. vol. iii. p. 184. 



Desc. Head black ; labrum and base of the anteunaj rufous : 

 thorax rufous, with a dorsal black spot composed of two confluent 

 ones, not reaching the anterior margin : elytra bright greenish- 

 blue : exterior margin, suture, and tip rufous ; this color is a 

 little dilated behind the humerus ; pectus rufous; about the base of 

 the feet black : postpectus and venter black, incisures of the 



