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



CEMONUS, Jurine. 

 Cemonus, Jurine, Hym. p. 214, (1807). 



% . Head very transverse, being one-third as long as broad, sides 

 angular, retreating behind ; eyes reaching to the middle (in a trans- 

 verse sense), of the head, aligned posteriorly with the two posterior 

 ocelli, vertex raised, convex, sides of the front converge rather rapidly 

 towards the clypeus, which is short and broad, with the front edge 

 rounded; front of head slightly depressed behind the antennae, 3d 

 joint of labial palpi rapidly thickening towards the tip; clavate; 4th 

 joint clavate, but longer and more cylindrical; 5th and 6th shorter and 

 cylindrical, subequal in length ; maxillary palpi thickened, sub-cylin- 

 drical, larger than the two terminal joints of the labial palpi, otherwise 

 as described in 9 • 



9 . Head large cuboidal, the sides narrow somewhat behind ; ocelli 

 approximate, placed in a triangle; eyes within slightly concave, 

 larger and nearer together than in Pemphredon ; front narrows towards 

 the clypeal region much more than in Pemphredon. Below the antennae 

 covered with a silvery pubescence; the clypeal region presents a 

 lozenge-shaped area; antennas a little longer than in Pemphredon ; the 

 2d joint is but a little larger than 3 and 4, as in Pemphredon, but the 

 4th joint is much the shorter; the mandibles much of the same size 

 and proportions as in Pemphredon. Thorax much as in the other 

 genus, but narrowing more rapidly behind; the propodeum is not so ab- 

 ruptly bent down as in Pemphredon ; the triangular area above is much 

 shorter and more angulated. 



Primaries: 2d costal is not triangular as in Pemphredon, but oval 

 lanceolate, 1st s. c. space distinctly angulated on the lower side, rather 

 narrower than in Pemphredon. 2d sub-costal s. c. shorter than broad, 

 the sides nearly straight ; the outer side of the 2d median space is not 

 curved, and the 3d, or outer space is much narrower than in Pem- 

 phredon ; the 2d internal space is much shorter and broader than in 

 Pemphredon; the medio-subcostal recurrent of the secondaries is 

 nearer the middle of the wing than in the above mentioned genus, the 

 nervules within being shorter and more curved. Legs very closely 

 approximate to those of Pemphredon, but the forelegs are slender and 

 not so hirsute. Hind tibiae trigonate, spur longer than in Pem- 

 phredon. 



Abdomen oval, with a rather long curved pedicel, which is longer 

 than in Pemphredon; the abdomen itself shorter and thicker; tip of 

 the abdomen smooth. 



