LeConte.] 



TOMicixi. 347 



Group I. Cortbyli. 



In this group the species are mostly of very small size, and are easily rec- 

 ognized bj^ the club of the antenna?, which is pubescent and annulated with 

 nearly straight sutures on both sides. One species of Micracis {hirtellu^\ 

 as will be seen below, has a nearly similar club, and shows thereby a re- 

 semblance to the present group, but is otherwise so closely allied to the 

 other Micracis that I have not been disposed to separate it from them. The 

 funicle varies from one to five joints; ths tibiae are serrate or ridged trans- 

 versely on the outer side; the tarsi are slender, the fourth joint distinct; 

 fifth long, with simple, divergent claws. The anal segment of the J^ is oc- 

 casionally visible from beneath. 



The genera may be thus separated : 



1. Funicle 1 -jointed i 2, 



" 2-5-jointed 3. 



2. Body robust CORTHYLUS. 



Body slender MONARTHRUM. 



3. Outer part of funicle rather slender PITYOPHTHORUS. 



very short HYPOTHENEMUS. 



CORTHYLUS Er. 



The body is much more robust than in Monarthrum, and the upper sur- 

 face is strongly punctured. The club of the antennae, connected with the 

 1-jointed funicle by a short slender peduncle, is much larger, opaque, finely 

 pubescent, not fringed. The front tibia? are flattened and margined on the 

 outer face, but there are no transverse ridges as in Monarilirum, and only 

 three acute teeth on the anterior edge near the tip; the tarsi are less slender, 

 the 1st joint is a little shorter than the 2d; the 2d and 3d are equal, the 

 4th small, 5th as long as the 2d and 3d united, slender, claws divergent, 

 simple, ventral segments subequal, 5th not longer than 4th, truncate; 

 pygidium convex, partly inflexed, distinctly visible from beneath; 1st ven- 

 tral suture deeply impressed. 



The pronotum is marked with a fine lateral line near the hind angles, 

 and along the base; the prosternum is extremely short in front of the coxa?. 

 Neither of these characters occurs in Monarthrum fasciatum, but the first 

 of them exists in the other species which I have referred to that genus. 



1. O. punctatissimus. Crypiurgus pimct. Zimm., Trans. Am. Ent. 

 Soc. 1868, 144. 



(^. Head flattened, opaque, slightly and broadly concave at the middle. 



9 . Head slightly convex, shining, punctured. 



Middle, Southern and Western States; rare. Length 4 mm.; .15 inch. 



MONARTHRUM Kirsch. 



In this genus the body is elongate and cylindrical; the scape of the an- 

 tennae is long and slender, the funicle of but one short joint, the others being 

 absorbed in the club, which is rounded, very much compressed, with two 



