Descriptions of Its Immature Stages, and Observations on Its Horal Host (Passifloraceae)

Information on the nesting, foraging, and mat-ing biology ofAnthemurgus passiflorae Robertson is presented based on observations ofa population in Austin, Texas. The population is multivoltine with the late spring-summer flight period bounded by the flowering period ofPassiflora lutea, its only known floral host. Nest arrangement indicates that the bee is weakly gregarious, with one female per nest. Nest architecture is simple, differing from that of its close putative relatives only in features related to nest reuse within a season. Females av-erage six pollen trips per day, apparently provi-sioning one cell per day during peak Passiflora bloom. In behavior novel for panurgine bees, fe-males scrape pollen from the Passiflora anthers with their mandibles. Despite gregarious nesting, mating and mating attempts were observed only at Passiflora flowers. Data on nectar and pollen production of P. lutea are presented. The mature larva ofAnthemurgus passiflorae is described, illustrated, and compared with larvae of other known panurgines. It resembles closely those of other Anthemurgini (Protandrena, Pseu-dopanurgus, Pterosarus, Heterosarus, Parasarus