WILLIAM G. DIETZ 127 



Thorax ivory yellow, shining. Pronotal scutum with pale brownish stripe 

 each-side of median line; scutellum brownish anteriorly. Lateral praescutal 

 stripes chestnut brown, curved slightly outward, anteriorly; the median stripe 

 reddish-brown, with paler median line, and narrowed posteriorly. Scutum 

 concolorous, polished, each side with two large, coalescent, reddish-brown 

 spots, the antero-exterior spot being the smaller. Scutellum and postnotum 

 concolorous, the former slightly, the latter more markedly, inf uscate along the 

 middle. Legs slender, yellowish, pubescence very short, black, appressed, 

 tibiae slightly inf uscate at tip, outer joints of tarsi brownish; metatarsi longer 

 than the tibiae. Wings hyaline with yellowish tint, costal cells pale yellow, 

 stigma brown, costo-apical portion somewhat inf uscate; veins C, Sc and Cu 

 yellowish, others brown. Costal veins, vein R and veins M 1 ' 2 and 3 , finely and 

 sparsely setulose. Venation as in figure. 



Abdomen sordid yellow, shining, with ill-defined, pale brown dorsal stripe, 

 the apical half of the seventh and eighth tergite nearly entirely light brown; 

 a lateral row of black strigae. Venter pale, eighth sternite with V-shaped 

 incision, the margin of which is fringed with stiff, yellow hairs, longer and form- 

 ing a pencil on the somewhat prominent, lateral angles of the incision. Hypo- 

 pygium yellow; ninth tergite brown, moderately impressed anteriorly, a deep, 

 rounded impression posteriorly and emarginate in the middle of the posterior 

 border; each side of this emargination and from beneath the margin, projects 

 a black, tooth-like process. Outer appendages lanceolate, attenuate outwardly 

 and incurved towards each other. 



Holotype: d 71 ; Plummer's Island, Maryland. July 28, 1912. 

 (W. L. McAtee.) 



Paratypes: one male, Hazleton, Pennsylvania, August 20, 

 1912, (W. G. Dietz) has the lateral abdominal strigae, much more 

 marked; one male, Ridgeway, Ontario, Canada, August 15, 

 1910, (M. C. Van Duzee), has the antennal flagellum darker, the 

 occipital triangle not apparent, the thoracic stripes ferruginous. 

 A male specimen from Aweme, Manitoba, Canada, (E. Criddle), 

 has the occiput less shining, the triangular spot distinct, but paler. 

 Stigma a shade paler than in the holotype. It is larger — length, 

 16.5 mm.; wing, 15 mm. 



In its shining occiput and unicolorous antennae flagellum, the 

 present species closely approaches P. sodalis Loew, but is readily 

 distinguished, by its very slender, pale yellowish-fuscous an- 

 tennae, the flagellar joints of which are not emarginate beneath, 

 the deeply incised eighth abdominal sternite and very deeply 

 impressed ninth tergite. 



TRANS. AM. ENT. SOC, XLIV. 



