Overview
A large and important family, well studied because of its medical and veterinary importance. The Australian fauna comprises about 200 described species. The subfamilies Pangoninae, Chrysopsinae, and tribe Tabanini were reviewed by Mackerras (1956-1971). The remaining Tabaninae (
Diachlorini
) comprise one species of
Lissimas
, about 35 of
Cydistomyia
, and about 75 of
Dasybasis
(D. Spratt, pers. comm.). This family is commonly referred to March flies or Horse flies.
Most of the Australian species suck blood, but some species of
Scaptia
appear to be exclusively flower-feeders, and the most primitive Pangoniini seem to live obscure lives among low vegetation; the females of a few of these have atrophied mandibles.
Cydistomyia
-like Chrysopinae, are common. Some of the blood-sucking species are pests of man and stock, and one northern species is known to produce sensitisation, with severe reaction to subsequent bites. However, none of our species occurs in such vast numbers as those of the subarctic zone of the Northern Hemisphere.
Tabanidae transmit loaiasis of humans in Africa and trypanosome infections of stock in the Old World tropics; but in Australia, disease transmission is, as far as known, limited to a filaroid nematode of kangaroos and wallabies (Spratt 1974).
Tabanid larvae are predators. The breeding places of the Australian species are extremely varied: in classical situations among floating vegetation in open swamps; in the mud of rivers; in more or less damp soil, among rotting vegetation; in dry or beach sand; or even in rot-holes in the trunks of
Casuarina
.
Description
The Australian species vary from small (6 mm long) to large (20 mm), and all are distinguished by having large eyes, segmented antennal flagellum, strong proboscis and labella, smooth bodies which are more or less hairy and often show dense pleural tufts, at least mid tibiae with apical spurs, and 1-segmented cerci in the female.
The commonest genera in southern Australia are
Scaptia
, thickset Pangoniinae with hairy eyes, and
Dasybasis
, hairy-eyed Tabaninae with bare basicosta and R4 appendiculate. In the north,
Tabanus
, with setulose basicosta,
Cydistomyia
, bare-eyed Tabaninae with bare basicosta and R4 without appendix, and
Lilaea
.
Distribution
The more primitive genera have a predominantly southern distribution in Australia, and are related to groups in New Zealand, South America and South Africa. Some old genera and subgenera, however, have a more northern distribution, and they are connected with corresponding African groups by a discontinuous band of species that extends around the Indian Ocean and also into the Pacific. The most highly evolved genera (
Chrysops
and
Tabanus
) appear to have dispersed from northern centres of evolution along with the eutherian mammals.