PREDATION ON THE HORN FLY (DIPTERA, MUSCIDAE) BY HISTER-BRUCHI

Hister bruchi Lewis, a histerid species from Argentina, was evaluated in the laboratory to determine its potential as a biological control a gent for immature stages of the horn fly, Haematobia irritans (L.). Wh en immature stages of the horn fly were exposed to varying numbers (on e - five) of adult beetles, horn fly population reductions were signif icantly greater at all levels compared with controls. However, increas ing the predator-prey ratio greater than 1:50 had no significant effec t on numbers of prey consumed by the beetles. This South American pred ator was more effective on the larval-pupal stages of the horn fly tha n on the egg stage.