Buffalo fly, or Buffalo gnat (Zo["o]l.), a small dipterous insect of the genus Simulium, allied to the black fly of the North. It is often extremely abundant in the lower part of the Mississippi valley and does great injury to domestic animals, often killing large numbers of cattle and horses. In Europe the Columbatz fly is a species with similar habits.
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Buffalo Fly (Haematobia exigua) 
Buffalo flies are usually found on the backs of cattle and only leave the host reluctantly. They usually only leave briefly to lay their eggs in fresh dung.
Buffalo flies are only found in northern Australia and Queensland. They are a parasite of hot climates (if temperatures fall below 21° C, these flies become sluggish) and high humidity.
Buffalo flies irritate cattle, causing worry and interfering with grazing. This affect leads to decreased productivity by retarding growth rates and depressing milk yield. This irritation can also lead to self-trauma and secondary infection. Although buffalo flies do suck blood, they are not known to transmit disease.
Buffalo flies are usually found around the withers, shoulders, flanks and eyes of cattle. Bos indicus cattle (tropical breeds) are less affected by these flies than are Bos taurus cattle (British and European breeds); even when Bos indicus cattle carry large populations of flies, they show fewer sores.
Control of buffalo flies involves a variety of measures 
Quarantine areas, interstate barriers and the treatment of animals from areas where buffalo fly occurs prior to movement;
Insecticides (these may be applied as sprays, dips and in back-rubbers); and
Dung beetles, which remove dung from the surface of the ground (partially successful).
Buffalo Fly traps, see below:


BUFFALO FLY TRAP DETAILS