156 



THE CANADIAN ENTOMOLOGIST 



and hind tibise at bases and apices, and basal joints of all tarsi, 

 ivory colour; mesopleurse more coarsely punctured than dorsum; 

 wings dusky; first abdominal segment finely sparsely punctured, 

 punctures closer towards apex, second and following segments 



more closely punctured. See figures 6 and 7 for structure of 

 seventh and eighth ventral plates. 



Female. — Length, about 5.25 mm. Similar to the male; face 

 below antennae more distinctly striatulate and more silky; a large- 

 mark on each side of face (see fig. 8), a spot on each side of prono- 

 tum, tubercles, a spot on tegulae, a spot on fore and mid tibiae at 

 base and a broad annulus on base of hind tibiae, ivory colour. 



Type locality. — Fargo, N.D. 



Type male collected Sept. 6, 1912 (Stevens No. 4154) ; allotype 

 female the same date (Stevens No. 4152) ; paratype female, Sept. 8, 

 1912 (Stevens No. 4194); paratype female, Aug. 26, 1912 (Stevens 

 No. 3947). All four specimens taken on Melilotus alba by Mr. 

 O. A. Stevens, after whom the species is named. 



Type Cat. No. 15530, U. S. N. M. 



Two paratype females in collection Mr. Stevens. 



In the classification of the genus by Metz, this species belongs 

 to his cressonii division and to the tridentulns-grossicornis group 

 and differs from these two species in the male having fewer teeth 

 on the outer margin of each wing of the seventh ventral plate, in 

 these teeth being stouter and more markedly turned up at end. 

 Neither of the older species has the propodeum strongly rugulose 

 nor so abruptly truncate, and the face markings are quite distinct,' 

 etc. 



