This was identified as a female Messiloptila otomita by Texas bee expert Jack Neff. The bee was found in the same location (on the same bush) as the male bee identified a few weeks ago in bug guide as Melissoptila otomita (at: https://bugguide.net/node/view/1611010 ).

At the time this female bee was found, there were many of these bees, both male and female, in the immediate area, all feeding on mallow (Malvastrum americanum var. americancum). Jack Neff reports that in Texas, he usually finds these feeding on Wissadula mallows.

More information on Melissoptila otomita can be found here:

(1) LaBerge, Wallace E. “The genera of bees of the tribe Eucerini in North and Central America (Hymenoptera, Apoidea)." American Museum Novitiates, no. 1837 (1957): 1-44 at 37-38. Available here: http://digitallibrary.amnh.org/handle/2246/2471

(2) https://www.wildbeestexas.com/melissoptila