Coelioxys chichimeca is a cleptoparasite and an important cause of mortality for several woodhole nesting pollinator bees in Costa Rica. We studied the behavior of this parasitic bee towards one of the more common host bee, Centris (Heterocentris) bicornuta. The female parasitic C. chichimeca were attracted to host bee, C. bicornuta nest cells that contained pollen, but only exhibited interest in entering and ovipositing when these host cells contained nectar. This interest was exhibited in three different ways: (1) the female parasite landed near the host bee’s nest entrance and waited for the host bee to exit her nest cell before entering; (2) the female parasite entered briefly, re-emerged and re-entered with abdomen first; and (3) the female parasite entered the host bee nest as in (2), but did not exit and re-enter due to larger nest holes, where she could presumably turn around in any direction to lay the egg. We also found that female parasites would briefly hover in front of vials that contained pollen, but would land nearby when the vial contained nectar. Additionally, eggs of the female parasite were inserted horizontally in the wall of the host bee cell, primarily in the upper half. Larvae of these parasites hatched before the host bee egg and with their sickle shaped mandibles, killed any host bee egg or larva present and consumed the nest provisions. Host bees returning to a parasitized cell often removed the nectar, presumably in an attempt to remove the parasite egg.