20 Myron Harmon Szvenk 



ing, tergite 2 with large subpyriform yellow spots, 3 with 

 smaller spots, 4 and 5 with spots often obscure or wanting, 6 



with a transverse spot ; size larger, 7-10 mm 8 



7. Abdomen darker red, the basal half of tergite i black right across 

 and only infrequently with yellow markings, tergites 2 and 3 

 spotted as above, 4 and 5 usually unspotted, transverse spot on 

 6 often divided ; size smaller, 6-8 mm lO 



8. Apex rather narrow, feebly bifid ; mesoscutum black with two red 

 lines; superior orbits black; mesopleura and propodeum 

 wholly black, anterior legs yellowish in front, reddish behind, 

 the bases of the femora with a black spot; 9-10 mm. . .vicinalis 



8. Apex broader, strongly bifid; mesoscutum red with a median black line; 

 superior orbits red ; mesopleura mainly red varied with black. 9 

 9. Propodeum black ; mesoscutellum more broadly subbilobate ; fla- 

 gellum red with a fuscous line above ; red color on mesoscutum, 

 pleura and mesoscutellum brighter ; anterior legs yellow, 

 brighter at the knees, bases of the femora behind with a black 



spot; face below antennae yellow; 7-9 mm cressonii 



9. Propodeum red with a black median line; mesoscutellum more 

 acutely subbilobate ; flagellum red with only the tip of the scape 

 and four basal joints blackish above; red color on mesoscutum, 

 pleura and mesoscutellum darker, less bright; anterior legs 

 red, yellowish at the knees, scarcely any black at bases of 

 femora behind ; face below antennae with black sutural lines 

 extending from bases of antennae nearly to lateral apices of 

 clypeus ; 9 mm defressicauda 



10. Mesoscutellum black varying to red, or red or yellow spotted ; meso- 

 scutum black, not obviously stained with red ; mesopleura with 

 only a small yellowish or reddish spot below tubercles, or none; 

 smaller, 6-7 mm sayi 



10. Mesoscutellum red; mesoscutum with large lateral areas red or red- 

 dish ; mesopleura usually with large red spots ; larger, 8 mm. 



propiiiqua 

 II. Abdomen red with large yellow lateral spots on tergite 2, some- 

 times connected to form a band, similar spots on 3, frequently 

 small lateral spots on 4 and occasionally on i, 5 usually immac- 

 ulate, 6 usually with a band or two spots; 6-8 mm. . .illinoiensis 

 II. Abdomen chiefly black, the apical margins of tergites 2-4 some- 

 times suffused with reddish, 2-6 with bright yellow bands, 

 sometimes more or less constricted anteriorly or interrupted 

 on middle of 2-4 but always complete on 5 and 6, a complete 

 band on i yellow, stained with reddish or wholly reddish, those 

 on 2-5 with more or less emargination on the lateral posterior 

 margin, often cutting through on 5 12 



12. Anterior orbits converging below, the interorbital width at narrowest 



20 



