NORTH AMERICAN COLEOPTEKA. 201 



9IY0CHR01IS Erich. 

 The species of this genus are of oblong form and clothed with 

 scaly vestiture. The sides of the thorax are usually dentate. 

 Three species occur in our fauna: 



Thorax distinctly tridentate at sides. 



Thorax wider than long; vestiture of surface uot dense and easily removed. 



flentivolli$i. 

 Thorax longer than wide: vestiture close and persistent; form more slender. 



IOIlglllll<«. 

 Thorax not dentate at the sides sqiiainosiiK. 



In Lefevre's " Catalogus Eumolpidarum" a M. plagiatu.s Meh. is 

 recorded. This is a variety of Xanth. villosula. 



M. deiiticollis Say. Jour. Acad, iii, p. 448; edit. Lee. ii. p. 215. 



The vestiture consists of rather small scales, cinereous and brown 

 intermixed, not closely placed, and permitting the bronze color of 

 the surface to be readily visible. The anterior tibije in both sexes 

 are acutely and rather strongly toothed below the middle. In the 

 male the last ventral segment has a small fovea, the apical maro-in 

 broadly emarginate. In the female there is no fovea and the tip of 

 the segment obtuse. 



This species varies considerably in size, from .18 to .28 inch. 

 Specimens of the latter size, collected by E. A. Schwarz, at Columbus, 

 Texas, are rather more densely clothed with scales than the other 

 specimen before, and have consequently a more luteous appearance, 

 but they do not seem to dijffer specifically. 



Occurs from Illinois to Texas and Florida. 



M. longiiliis Lee, Proc. Acad. 1858. p. 86. 



The vestiture consists of narrow and acute brownish scales, more 

 densely placed than in denticollis. The rows of punctures of the 

 elytra are also less ch)sely placed, so that there is a well marked in- 

 terval between the rows. The anterior tibiae have no distinct tooth, 

 there being merely a .slight angulation below which is a slight sinua- 

 tion. The last ventral of the male has a shallow fovea, the tip of 

 the segment truncate. 



As in denticollis, the thoracic teeth are somewhat variable in their 

 prominence. 



Occurs at Yuma, Cal., and Arizona. 



j?I. sqiiaino!iiiis Lee. Col. Ks. 1859, p. 24. 



The vestiture consists of closely placed, elongate-oval cinereous 



TKANS. AM. ENT. SOC. XIX. (2fi) JULY, 1892. 



