l66 TRANS. ST. LOUIS ACAD. SCIENCE. 



extreme tip, where they expandlnearly to their basal width. Venter in- 

 flated and longitudinally carinate. Legs black ; front knees, extreme base 

 of all 6 tibiae, basal \-\ of the ist tarsal joint in all 6 legs, and in the 4 front 

 legs the whole of joints 3 and 4, but in the hind legs of 4 only, all white. 

 Wings hyaline, the front ones slightly tinged with smoky yellow ; veins 

 black ; stigma black, its basal \ white. Radial area nearly 4 times as long 

 as wide. Length $ .93 (over i.cxD Say) inch. Front wing $ .64 inch. 

 Ovip. 1. 10 inch. 



One $ , taken in August on a decayed Elm infested by PhyseC' 

 nemum brevilineum^ Say, and Leptura americana^ Hald. ; c? un- 

 known to me. Distinct from Cincticornis^ Cress., by the white 

 annulations of the legs. Say, in referring this species to Acatiitus, 

 evidently mistook the prolongation of the 8th dorsal joint of the 

 abdomen for the prolongation of the 6th ventral found in that and 

 other allied genera. 



