This is a medium-sized cleptoparasitic bee which is yellow and black, although some females may be red, yellow and black. The bees can be very obvious on some heathland sites, being more readily found than their hosts (bees of the Andrena denticulata group).

A predominantly black bee; the abdomen is narrow and cylindrical, which is probably an adaptation to using small-bore beetle burrows as nest sites. The males have the final segment of the abdomen modified to form a two-pronged peg which is used to hold on inside flowers during the night or in poor weather, which gives a good method for recording the bees under such conditions.