192 Trans. Acad. Sct. 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 
BAPIONE Sa scanss dahe's peeneirke sen yenencen in sled Shae DeeL ee Scopaeodera | 
I have been unable to obtain specimens of the Mexican 
Huscopaeus Shp., 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. 
Leucorus 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 and wider than the prothorax.......ccccecssecsesece 2 
Elytra subequal in length to the prothorax and but little wider....... osee 8 
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, 
theeyes 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 
