36 PROCEEDINGS OF THE NATIONAL MUSEUM voi,. s2 



Propodeiim with the areas laterad of the enclosure even more shiny 

 than in the male because of the lack of shagreening. Pygidium 

 about twice as long as wide. 



Lengtli, 9 mm. 



Type. — U.S.N.M. No. 44213, male, one half mile west of Thoreau, 

 N.Mex., July 24, 1929, on Salsola festifei\ lot 5823, no collector's 

 name; allotype, Meadow Grove, Nebr., July 18, 1929 (C. N. Ainslie). 



This is the only species of the genus known to me in which the 

 propodeum is entirely without definite sculpture on the areas con- 

 tiguous with the enclosure. 



PSEN (MIMESA) ARIZONENSIS, new species 

 Plate 1, Figures 15, 16 



Male. — Readily distinguishable from most of its allies by the en- 

 tirely red first, second, and third abdominal tergites. The antennal 

 flagellum is brown above and broadly yellow below, the scape is 

 black, and the hairs of the face are silvery white. The coxae and 

 femora are black, the tibiae dull yellow and broadly browned 

 apically, and the hind tarsi are dull brownish yellow, with the apices 

 of the segments paler. Stigma dark brown, paler at extreme base. 



Flagellum but slightly thickened apically, the penultimate seg- 

 ment longer than thick, none of the segments with well-developed 

 elevations ; clypeus slightly produced centrally and with a very nar- 

 row median notch; front quite closely punctured and with fine sha- 

 greening, a slight impressed line across behind the posterior ocelli. 

 Mesonotum with moderate punctures and slightly alutaceous, the scu- 

 tellura more shining and sparsely punctured; propodeum with the 

 enclosure poorly defined and closely reticulated (pi. 1, fig. 15), the 

 lateral areas striate to curve. Petiole of abdomen a little shorter 

 than swollen part of the segment and not so long as hind femur, 

 convex above, the laterodorsal edges not definitely carinate, the 

 lateroventral edges partly carinate. Legs and wings normal. 



Length, 8 mm. 



Type. — U.S.N.M. No. 44214, from Tucson, Ariz., on Blgelovia 

 hartwegi (Towmey). 



PSEN (MIMESA) PUNCTIFRONS, new species 



Male. — Face white haired; underside of antennal flagellum yellow 

 on entire extent except base of first segment. Apex of first, all of 

 second, and anterior two thirds or more of third tergite red. Legs 

 black, fore and mid tibiae yellowish brown, becoming fuscous or 

 black below; fore and mid tarsi brownish yellow, hind pair dark 

 brown centrally, becoming black at base, and paler brown apically. 

 Wings grayish, stigma dark brown to black. 



