192 Trans. Acad. Sci. of St. Louis. 



nation, the inner teeth distinct, simple and aciculate, the outer very 

 minute or subobsolete; gular sutures very fine, rather widely separated, 

 feebly arcuate, most approximate slightly before the middle. Sonoran 

 regions Scopaeodera 



I have been unable to obtain specimens of the Mexican 

 Euscopaeus Slip., or of the true Polyodontus Sol., for compar- 

 ison. In the catalogue of Heyden, Reitter and Weise, the lat- 

 ter of these genera is made the receptacle for most of the Euro- 

 pean Scopaei, but I can find no structural difference between 

 the species so listed and those which are held to represent 

 the true Scopaeus. It is my recollection that Polyodontus 

 Sol., is a genus differing distinctly from Scopaeus and inhab- 

 iting Chile, but I have no means of confirming this at present. 



Leucorns n. gen. 



The prothorax in this genus is more oblong and with more 

 apical and strongly defined anterior angles than in any other 

 type of American Scopaei, and, from all other genera except 

 Orus and Pycnorus, it is distinguishable at once by the wider 

 neck, which varies from nearly a fourth to almost a third as 

 wide as the head. From Pycnorus it departs widely in habi- 

 tus, owing to the distinct thoracic angles, and, from both 

 Orus and Pycnorus, it differs radically in the form of the 

 labrum and obsolete external labral teeth. The color of the 

 body is always pale ferruginous, differing conspicuously from 

 the uniform black or piceous of the genera mentioned, and 

 the few known species are confined as far as known to the 

 regions west of the Mississippi River, excepting probably the 

 true Pacific coast fauna. The four species in my cabinet 

 may be defined as follows : — 



Elytra much longer aDd wider than the prothorax 2 



Elytra subequal in length to the prothorax and but little wider 3 



2 — Form rather stout, moderately convex, parallel, pale rufo-testaceous 

 in color throughout the body, legs and antennae; lustre rather shining; 

 head well developed, minutely, not densely punctate, slightly elongate, 

 the eyes rather large but only feebly convex and not prominent, the sides 

 behind them very feebly converging and just visibly arcuate to the 

 broadly rounded basal angles, the truncate base obviously narrower than 

 the width across the eyes; antennae evidently shorter than the head and 



