author(s)
Aguib Sihem, Benachour Karima, Maghni Noudjoud and Louadi Kamel

abstract
The analysis of six Osmia tingitana nests found in snail shells showed that the female selects shells belonging to the Hygromiidae family and whose diameter was between 1.8 and 3.5 cm. The nest building materials consist essentially of sand, small pebbles, plant fragments (stems or flower petals) mixed with the pollen grains. The nest was closed with a cap formed of a greenish paste consisting of pine needles chewed and mixed with the bee saliva and pieces of the shell. The number of cells per nest was variable, and range between 4 and 7 cells for multicellular nests.The different development stages were found in the nests analyzed with observation for the first time in one nest of the parasitic species of osmia, namely a cuckoo wasp, Chrysura barbata of the Chrysididae family.