440 



U. S. NATIONAL MUSEUM BULLETIN 216 



PABT 3 



Figures 243, 244. — Localities: 243 (left), Mesostenus albinotaius promptus; 244 (right), 



M. liogaster. 



Co., Mich.; September 11 at Gazelle, Calif.; September 14 in Gratiot 

 Co., Mich.; and September 18 at Bells Corners, Ont. 



Our collections have been from places where there are weeds, grass, 

 and scattered trees or bushes. 



This subspecies is transcontinental, m_ostly in the Transition zone. 



2. Mesostenus liogaster, new species 



Front wing 6.2 to 8.0 mm. long. Structurally similar to M. albi- 

 notatus except as follows: Body sculpture a little smoother and with 

 punctures a little coarser; punctures just below middle of mesopleurum 

 crowded and irregular in shape but never completely obliterated by 

 rugulosity; second tergite of female subpolished or wealdy mat, with 

 very small punctures that are separated by about 5.0 their diameter; 

 ovipositor sheath about 0.93 as long as front wing. 



Male: Colored like the male of M. albinotaius except as follows: 

 White on frontal orbit averaging a little narrower; clypeus entirely 

 white, white with more or less of the median part black, or entirely 

 black; face without median white marks; second segment of labial 

 palpus mostly white; pronotum entirely black; hmd femur varying 

 from entirely black to ferruginous with its apex infuscate; wings 

 faintly infuscate; and abdomen ferruginous except that genitalia are 

 fuscous and tergite 8 more or less infuscate. 



Female : Black. Palpi fuscous, the last three segments of maxillary 

 palpus usually paler; flagellum Avith an obscure whitish dorsal stripe on 

 one to three of its median segments; wings weakly to strongly in- 

 fuscate; front and middle femora brown or blackish, more or less 

 ferruginous in front, especially apically; front and middle tibiae fulvo- 

 ferruginous in front, the rest dark brown; front and middle tarsi dark 



