328 BULLETIN 45, UNITED STATES NATIONAL MUSEUM. 



MALES. 



Flagellnm brownish-yellow or pale 3 



Flagelluui brown. 

 Pedicel and second funiclar joint equal, the first shorter. 

 Pleural piece beneath the anterior wing smooth, net striated; terminal club 



joint only i longer than the penultimate I. ni«riclavu8 Ashm. 



2. Pedicel a little shorter than the second funiclar joint. 



Pleural piece beneath the anterior uing smooth, not striated ; terminal club joint 



twice as long as the penultimate ; first funiclar joint twice as long as 



thick P. PALLIPES Say. 



Pleural piece beneath the anterior wing striated ; terminal club joint not twice 



as long as the penultimate; first funiclar joint as wide as long. 



P. CANADENSIS PrOV. 



laooybus nlgriolavus Ashm. 

 Bull. No. 1, Col. Biol. Assoc, p. 10. 



9 . Length, 3.4 to 4""". Black, closely, finely punctate, the face ru- 

 gulose. Head subquadrate, the occiput concave. AntennsB 10-jointed, 

 brownish-yellow, the 6 terminal joints, constituting the club, black; the 

 pedicel is more than twice as long as thick, the two following funiclar 

 joints a little shorter, cylindric, the second obliquely truncate at tip, a 

 little shorter than the first; the joints of the club a little stouter and a 

 little longer than thick, the last being the longest and less than twice as 

 long as thick ; parapsidal grooves distinct, converging but not quite meet- 

 ing posteriorly. Scutellum convex, sparsely covered with a fuscous pu- 

 bescence, and separated from the mesonotum by a transverse furrow at 

 base. The mesopleura alone smooth and shining, with a large, deep 

 fovea on the disk. Metapleura and metathorax rather densely pubes- 

 cent, the former divided by a longitudinal grooved line or impression. 

 Legs brownish-yellow; all coxie black. Abdomen a little longer than 

 the head and thorax together, polished, the petiole roughened, pubes- 

 cent, and about one-third longer than wide. Wings dusky hyaline, 

 pubescent. 



The 3 differs in having the second funiclar joint distinctly longer 

 than the first, tlie club being jialer, with the joints about twice as loag 

 as thick. 



Habitat. — Greeley, Colo. , ' r 



Types in Coll. Ashmead. 



Described from several specimens. 



Isocybus pallipes Say. 

 (PI. XIII, Fig. 5, F.) 



iPlatygoBter pallipes Say, Lee. Ed. Say., Vol. 1, p. 383; Ashm. Can. Est., xix, p. 

 • 132; Cr. Syn. Hym., p. 250. 



$ 9 . Length, 'd.b""^. Black, very finely, closely punctate ; legs honey- 

 yellow, the coxae black, pubescent; thorax long, the mesonotum with 

 2 distinct furrows; mesopleura polished, not striated posteriorly; meta- 



