Figure 20 in Investigations on the Biologies and Immature Stages of the Cleptoparasitic Bee Genera Radoszkowskiana and Coelioxys and Their Megachile Hosts (Hymenoptera: Apoidea: Megachilidae: Megachilini)

Figure 20 is a close-up in ventral view of the anterior end of the first instar of Radoszkowskiana rufiventris from which the piece of chorion had been torn away when host and parasite were separate. The peculiar stratum with a papillate outer surface covering the front of the labrum cannot be explained at this time and warrants further investigation to reveal its anatomy and function. Of special interest are the mandibles. Although, as stated above, we thought at first that each had a simple, curved, sclerotized apex, we discov-