On August 1991, three spiroplasmas (Tab 2A, Tab 2B and Tab 4C) were isolated from Haematopota sp. flies collected from Indre-et-Loire, France. Isolations were made at 28 degrees C in MD1 medium from ground individual flies, but not from external washings. All isolates adapted well to SP4 medium at 30 and 37 degrees C and were triple cloned before serological identification. Using the cross deformation test, the 3 isolates were compared with 42 known spiroplasmas isolated from diseased plants, flowers, various insects and ticks belonging to 25 serological groups. Each isolate cross-reacted with others and exhibited weak 1-way reactions with TABS-2 or PLHS-1, two spiroplasmas isolated in the United States from respectively Tabanus abactor Philip and Panorpa helena L, a scorpion-fly. These results suggest that Tab 2A, Tab 2B and Tab 4C together with TABS-2 and PLHS-1 may represent, members of a new serological supergroup.