Palaearctic Chelostoma bees of the subgenus Gyrodromella (Megachilidae, Osmiini): biology, taxonomy and key to species Author Müller, Andreas text Zootaxa 2015 3936 3 408 420 journal article 10.11646/zootaxa.3936.3.6 073d48e4-8e26-428b-b8cd-bac6a606fcbf 1175-5326 238286 9B737E02-FC85-4589-AA38-A3C18DEB6727 rapunculi species group Preoccipital ridge raised to a carina. Basal zone of propodeum distinctly sloping and usually only about half as long as metanotum. Anterior surface of tergum 1 shallowly concave. Females: Clypeus only slightly protruding or with flat narrow apical zone ( Fig. 5 ). Males: Median elevation on sternum 2 of uniform shape among species, roughly triangular in lateral view, its posterior surface evenly sloping, of half-elliptical shape and almost flat ( Fig. 12 ). Apical zone of sternum 4 without dense pilosity of yellowish hairs. Tergum 7 tripartite with one lower median tooth and two upper lateral teeth ( Fig. 6, 9 ), which are rarely fused to a straight uninterrupted transverse apical margin.