BY THOMAS G. SLOANE. 49 



Promecoderus ambiguus, n.sp. 



Lfevigate, form comparatively short, elytra much broader than 

 prothorax. 



Shining, upper-surface bronzed-black, with a greenish tinge, 

 undersurface rather piceous, legs piceous black, tarsi and . palpi 

 blown. Head large, without impression across vertex behind the 

 eyes ; clypeus slightly rugulose ; clypeal suture distinct, ending 

 in a short foveiform impression on each side ; the lateral 

 channel from above eye to base of mandible straight, not 

 oblique ; eyes round, prominent, inclosed behind ; post-ocular 

 prominences rather inconspicuous, about half the length of eyes ; 

 mentum with strong median tooth. Prothorax convex, almost as 

 long as broad (3^- x 3| mm.), truncate in front and behind, widest 

 about the middle ; sides dilatate in middle, shortly narrowed 

 behind ; marginal bonier narrow, not sinuate before basal angles, 

 stronger and entire on base ; a broad lightly marked trarisverse 

 impression a little in front of the base ; median line fine, very 

 lightly impressed. Elytra rather convex, short, oval (8 x 5-^ mm.), 

 rounded on the sides, broadest a little behind the middle ; 

 shoulders rounded ; suture lightly impressed ; lateral border 

 narrow ; marginal punctures as usual. Ventral segments smooth, 

 four last with a broad shallow round fovea on each side. Posterior 

 trochanters long and pointed at apex. 



Length 13, breadth 5^ mm. 



Hah. — Northern Territory of South Australia. 



A single specimen in my collection received from the Rev. Thos. 

 Blackburn of Adelaide. The last ventral segment has one 

 puncture on each side of the anus (therefore I believe it to be the 

 (J), and the anterior tibiae are without spongiose tissue below. In 

 these respects, and in the form of the posterior trochanters it 

 resembles P. distinctus, SI., which is its nearest ally among 

 previously described species. I have not been able to compare 

 them, but would note the more metallic colour of the undersurface 

 in P. distinctus. 

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