Flowers of Vicia sepium (left) and Lathyrus pratensis (right) a, b longitudinal slit in calyx due to primary nectar robbing by Andrena lathyri c, d flower with calyx removed showing lower side of standard (arrow), under which A. lathyri moves head and proboscis towards flower base e, f flower in top view with calyx, standard and wings removed showing nectary (ne), which is accessible only from above g, h normally developing fruits despite slit in the calyx (arrow) caused by A. lathyri.