Are these all males? I noticed Lipotriches (Austronomia) phanerura male (sleeping) group accumulations in my garden in late summer / early autumn; see Lipotriches (Austronomia) phanerura (Halictid Bee)
Yes. As far as I can see, they are all males. Males have chunky, angular hind legs while females have normal hind legs but with hairs for carrying pollen. In addition, the antennae are longer on males.