Osmia (Osmia) cerinthidis are dark bees with a metallic blue shimmer on the head and thorax and a metallic bronze or blue hue to the abdomen. Hair coloration of O. cerinthidis can be highly variable, ranging from light grey to intensely reddish-brown (Peters 1978). Female body length is 11 –12 mm. Male body length is 10–11 mm (Amiet et al. 2004).
(modified from Peters 1978 and Amiet 2004)
Osmia cerinthidis may be confused with O. rufa because of sometimes similar hair coloration (Peters 1978; Amiet 2004). Females can be distinguished from O. rufa by the shape of the clypeus, and males can be distinguished by the shape of the gonocoxites which are more digitiform apically in O. cerinthidis.
Osmia cerinthidis adults have been recorded in flight from April to July (Banaszak and Romasenko 1998).
Osmia cerinthidis nest in preexisting cavities such as the hollow stems of grasses, for example in Phragmites (Banaszak and Romasenko 1988). Osmia cerinthidis has also been known to nest in man-made cavities like drilled borings in wooden blocks (Banaszak and Romasenko 1998). Cell partitions and nest plugs are made of sand and earth dust glued with saliva (Banaszak and Romasenko 1998).
Osmia cerinthidis is native to southern Europe, and specimens have been recorded in central Europe from the eastern Alps to Ukraine (Amiet et al. 2004).