2t2 COLEOPTERA OF NORTH AMERICA. 



prothorax armed with numerous small teeth. The head is com- 

 paratively large, the eyes strongly granulated, distant, trans- 

 verse, feebly eniarginate; the antennae are slender, half the length 

 of the body in the % , shorter in the 5, sparsely and coarsely 

 punctured ; the 3d joint is scarcely longer than the 4th ; porifer- 

 ous spaces commencing on the under surface at the distal end 

 of the 3d joint, gradually becoming larger until they cover the 

 outer four joints, which are sculptured with fine longitudinal 

 elevated lines. 



The prothorax frequently differs in the two sexes, being nearly 

 quadrate in the % , densely punctured with smooth separate 

 facets, narrowed in front in the ?, more coarsely punctured to- 

 wards the sides, uneven on the disk. 



The species form two groups : 1. Mandibles nearly horizontal, 

 prolonged in the %. 2. Apagiognathus Thovi. mandibles ver- 

 tical. These characters do not seem to be of generic value. 



M. gnat.ho Lee. from Texas belongs to the 1st group, and is 

 further distinguished by the metatlioracic episterna having the 

 inner outline concave; this form is recognized by Lacordaire as 

 a distinct genus, Notliopleurus (1. c. viii. 125), but the difference 

 scarcely merits such separation ; in the % the metasternum has 

 two large densely villous spaces, in the 9 the same portion is 

 clothed with long soft pubescence. 



Tribe III.— DEROBR.4CHI1VI. 



In this tribe the form is somewhat more slender than in the 

 preceding ; the head is smaller, the eyes coarsely granulated, 

 very large, transverse, reniform, and approximate, both above and 

 below, somewhat larger in the males than in the females. The 

 mandibles are horizontal, acute, and alike in both sexes. The 

 antennae are 11 -jointed, nearly filiform in the 9, thicker at the 

 base in the %. The sensitive pores commence on the outer half 

 of the 3d joint, and cover the whole surface of the 4th and fol- 

 lowing joints, arranged in longitudinal grooves, separated by fine 

 elevated lines. The prothorax is alike in both sexes, armed with 

 three acute teeth on each side, the front one of which is in D. 

 gemivatus double, and occasionally even divided into two large 

 teeth, so that the thorax becomes really 4-dentate. The legs are 

 slender, sparsely punctured with the hind femora deeply sulcata 



