With reference to the work of G. CARCH1NI & E. ROTA (1985. Odonatologica 14; 239-245), data are presented on 29 spp., relative to the chemical and physical features of their larval habitats. The ecological tolerance of 13 spp. is discussed. While Lestes viridis, Ischnura graellsi, Anax imperator, Crocothemis erythraea and Sympetrum striolatum are ecologically adaptible. Boyeria irene, Onychogomphus forcipatus unguiculatus, O. uncatus and Cordulegaster boltoni are considered useful indicators for the water quality assessment.