This study encompasses a number of field encounters by the author and others with nests of representatives of three of the four genera of the little-known New World andrenid subfamily Oxaeinae. Species treated include Protoxaea gloriosa Fox, Oxaea flavescens Klug, O. austera Gerstaecker, and Mesoxaea nigerrima (Friese), leaving the nesting biology of only the monotypic genus Notoxaea completely unknown. Nests, all subterranean, are described and diagrammed, and each is reported to consist of a moderately to very deep main burrow with vertical cells occurring at the lower end attached to the main burrow by subhorizontal lateral tunnels, each of which is closed immediately after egg deposition. To the extent known, eggs, mature larvae, and pupae are described. Two known cleptoparasites of the subfamily are reported: Triepeolus kathrynae Rozen, hosted by P. gloriosa, and Thalestria spinosa (Fabricius) (= T. smaragdina Smith), which attacks nests of both O. flavescens and O. austera. The mature larvae of these cleptoparasitic Nomadinae are described and illustrated as an appendix.