A thick-headed fly, Myopa tessellatipennis Motsch, emerged from a pupa which had been found in a dead bee, 13 cm deep in the ground in a cluster of nests of Andrena argentata. The pupa had been found in August 2007 in Schoorl; it emerged in april 2009. April is so early in the year that we think that the fly isn't a parasite of A. argentata, but of A. barbilabris, which also had clusters of nests in the same area in the spring.