This cleptoparasitic genus can be fairly common at some sites where their hosts are present. Eight species so far confirmed from Vermont, all of which are cleptoparasites of leafcutter bees (Megachile). Often found cruising low over areas of sparsely vegetated sand. Most species are thought to have several different host species.

Genus level ID: Females have distinctly pointed abdomen, while most males have an assortment of spines. All the VT species are superficially quite similar, but several species have distinctive characters that can occasionally be seen in photos.

Simplified Key to Female Coelioxys in VT

Legs all black

Coelioxys alternatus -> Uncommon to rare.

Coelioxys porterae -> Uncommon to rare.

Coelioxys moestus ->

Coelioxys sodalis -> Hairy. Uncommon, northern species.

Leg with red, at least on the tarus

Coelioxys modestus -> S6 fan shaped, T6 with small bump at tip. Small and moderately common.

Coelioxys octodentatus -> T6 with moderately distinct shoulders, femur and tibia reddish.

Coelioxys rufitarsis -> T6 with distinct shoulders, femur and tibia black. Fairly common, at least around sandy sites.

Coelioxys sayi -> Legs usually mixed red and black, clypeus margin concave.

Unless otherwise specified, photos are courtesy of Margarita Miklasevskaja at PCYU with funding from NSERC-CANPOLIN.