Hylaeus (Prosopis) illinoisensis (Robertson, 1896)

Zarrillo, Tracy A., Stoner, Kimberly A. & Ascher, John S., 2025, Biodiversity of Bees (Hymenoptera: Apoidea: Anthophila) in Connecticut (USA), Zootaxa 5586 (1), pp. 1-138 : 103-104

Hylaeus (Prosopis) illinoisensis (Robertson, 1896)

Illinois Masked Bee

Notes: The putative male from Connecticut has been rechecked against Mitchell (1960), Oram (2018), and an unpublished key written by Arduser (2020). Our male specimen exhibits the following diagnostic characters: T1 shiny, very faintly punctate (visible only at 40x), with T2 densely punctured and less shiny (visible at 10×); hind tibia mostly yellow with a small dark maculation on the posterior surface only. We are accepting this specimen to be H. illinoisensis as understood by the preceding descriptive accounts. This species has been reported from many states and provinces, but it is poorly known, and it is possible that many records are unreliable. Regional Hylaeus illinoisensis males with yellow or mostly yellow hind tibiae are often identified as this based on Mitchell (1960), however they can now be rechecked against Oram (2018) and Arduser (2020) as well for further validation. The species may be associated with wetland areas at least in Manitoba (Gibbs et al. 2023).

Material examined. See Zarrillo et al. (2016)