2 PKOCEEDINGS OF THE NATIONAL MUSEUM vol.79 



rugulose behind apical carina; areola impunctate, longer than broad, 

 with costulae not far behind middle; spiracles slitlike, close to 

 lateral carina. Abdomen very finely alutaceous, opaque, impunctate ; 

 postpetiole medially, and second tergite basally, faintly, longitudi- 

 nally striate ; gastrocoeli obsolete ; compression of abdomen begin- 

 ning on fourth segment; apical two tergites abruptly shorter than 

 jareceding; sheath projecting, hardly three times as long as broad. 



Ferruginous ; occiput medially, thoracic sutures, propleura largely, 

 apices of hind femur and tibia and their tarsi, apical margins of 

 tergites 2 to 5 and tergites 6 and 7 entirely, black to piceous; subalar 

 tubercle and scutellum yellowish ; antennae ferruginous, apices black ; 

 wings hyaline, faintly yellowish, stigma pale, veins black. 



MaJe. — Differs from female principally as follows: Ocelli slightly 

 larger; eyes parallel within; face narrower; malar space distinctly 

 shorter than basal width of mandible; antennae very slender, not 

 involute; metapleurum longitudinally rugulose below; propodeum 

 more shining, more or less rugulose above; abdomen finely punctate 

 beyond first tergite; gastrocoeli more distinct, transverse, at about 

 basal fourth of tergite, with a strong carina running to base of 

 tergite; abdomen only very faintly compressed apically, tergites 

 gradually shorter, seventh abruptly shorter. 



Head black; face and under side of antennae yellowish, frontal 

 and lower posterior orbits reddish; thorax black, prescutum largehv, 

 lateral lobes anteriorly, and a spot in middle of mesopleurum, fer- 

 ruginous; scutellum, humeral angle of pronotum, subalar tubercle, 

 and proj)odeum except base, yellowish; front and middle leg^ 

 testaceous, their coxae and trochanters yellow; hind coxa yellow 

 above and at apex below, otherwise black, trochanters, base of femur, 

 tibia except apex and tarsus reddish to yellowish, femur otherwise 

 and apex of tibia black; abdomen paler than in female with first 

 tergite black at base and apex. 



Host. — LwpeHna stipafa Morrison. 



Type.—V.^.l^M. No. 42894, from Ames, Iowa. 



Nine females and six males from the type locality, the type, 

 allotype, and a paratype male reared from the type host by George 

 Hendrickson on July 25, 1929, the others reared by G. C. Decker 

 under Iowa Experiment Station No. 30. Also one female labeled 

 Prince Albert, June 24, 1913. 



Genus PHOTOCRYPTUS Viereck 



Photocnjptus ViEKECK, Proe. U. S. Nat. Mus., vol. 46, p. 379, 1913. 



Structurally this genus is closely allied to Acrorlcnus Ratzeburg, 

 and rearing records show it to be biologically related as well, both 

 being parasitic on wasps that use mud for their nests, such as 

 Eumenes and Sceliphro^i. 



