396 Dr. A. S. Packard, Jr's Revision of the 



leg. Abdomen as in the preceding species, slightly pedicelled, edges 

 angular, segments behind slightly contracted towards the sutures, black, 

 extreme tip grooved, channel not so large and distinct as in P. mandi- 

 bidaris. 



Length, .20— .22 inch. Indiana, (Say), Illinois, (Coll. Ent. Soc. 

 Phil.). Mass., (Coll. Harr.). 



Differs from the other species by its much smaller size, its fuscous 

 legs, narrow head, very smooth front, which is but slightly sericeous. 

 The whitish rings on the antennal joints of the male will readily dis- 

 tinguish the species, besides its small size. 



PSEN Latr. 

 " Psen Latr., Precis. (1796)." 



% . Head very transverse, short, nearly one-half as long as broad ; 

 vertex much compressed from before backwards, so that the vertex is 

 high, very convex, and the ocelli are very prominent, contiguous, 

 arranged in au equilateral triangle. A slight raised carina between 

 the origin of the antennae; the sides of the front contract narrowly 

 towards the clypeus, which is shorter than in the $ • Entire front, 

 from just below the ocelli, thickly pubescent; antennae very long, 

 filiform, scarcely clavate ; joints long, suture well marked. Thorax 

 and wings as described in $ ; tip of the abdomen acute. 



9 . Head subcubical, one-half as long as broad, corners subangular, 

 vertex compressed antero-posteriorly, so that the vertex is very high, 

 convex and with prominent ocelli, which are arranged in an equi- 

 lateral triangle, situated on the vertex. Eyes larger than usual, very 

 prominent, extending farther backwards than usual behind the middle 

 (in a transverse sense) of the head. A mesial raphe but no depres- 

 sion in front of the anterior ocellus. Sockets for the insertion of the 

 antennae large aud deep, surrounded by high ridges ; sometimes be- 

 tween these is a high crowded carina cleft mesially and longitudinally. 

 Front contracts rather rapidly towards the middle and opposite the 

 insertion of the antennas, which are inserted very high up; in front it 

 forms a broad, slightly convex region, which has parallel sides; and a 

 little below the middle is the posterior edge of the clypeus, which has 

 a very convex posterior edge, and is in front unusually straight, but 

 slightly convex. Labrum with a few long setose hairs arranged in a 

 semi-circle, those in the middle being; much larger than on the sides. 

 Maudibles broad at the base, triangular, tips incurved, very narrow 

 and unequally bidentate ; lingua terminates in two lateral terminal 

 lobes, not very deeply cleft; antennas scarcely elbowed, scape large and 



