Under SEM the silk weave in the snail-like cases ofHelicopsyche crispataandH. shuttleworthi, the two species present in Italy consist of several types of meshes. The silk which connects the sand grains of the external wall is made up of multi-layered threads forming irregular meshes. The sand grains of the vertical pillars in the wall of the centr al columella are held together by very loosely woven silk and are supported by thick silken threads. The pupal silken membrane consists of concentric threads and the pupal case is attached to the substrate by a disordered mass of silken threads. The two glands which secrete the silk are long, double folded tubes.