MORELLIA HORTENSIA (WIEDEMANN), A NEW LIVESTOCK FLY IN AUSTRALIA

Morellia hortensia , a fly not previously known from Australia, was found to be infesting livestock over much of northern Australia. Dissections showed that blood was present in the gut more frequently than in another livestock‐infesting fly, Musca fergusoni , and it is suggested that Morellia uses prestomal teeth on the proboscis to draw blood from soft tissue. Field observations were made on adults feeding on livestock, and breeding in cow dung, and the immature stages are briefly described and illustrated. The species shows similarities in habit to the face fly of North America, but is probably only a minor pest of livestock. The possible history of its introduction to Australia is discussed.