The Diptera-brachycera of Tasmania. Part II

Families Tabanidae and Therevidae. The Tabanidae are commonly called in Australia "March Flies," and in other parts of the world "Horse Flies" or "Gad Flies." The females are persistent bloodsuckers, and will attack man and animals indiscriminately.
The males are much rarer and less frequently met with than the females; they frequent flowers, whilst one Tasmanian species occurs settled on the ground in hot, sandy places, and the male of another species flies rapidly to and fro in the bright sunshine. The females of several species of Tabanus are common in the bush throughout the summer; the name "March Flies" is, however, somewhat inappropriate when applied to Tasmanian species, as specimens are seldom to be met with after the first few days of that month.
Family VI Therevidae. Flies of moderate size, of elongated or conical shape, the thorax and legs with distinct bristles ; distinguished from the Asilidae by the eyes not being protuberant from a sunk vertex, and by the head being set close against the thorax, instead of being attached thereto by a slender neck. Head about the same breadth as the thorax antenna? composed of three joints, with an apical style ; eyes either touching or separated in the male, always widely separated in the female. Thorax distinctly longer than broad, with presutural, suproalar, postalar, and prescutellar bristles ; scutellum with one or two pairs of marginal bristles. Abdomen either conical, or long and tapering. Legs slender, rather long, with distinct bristles.
Wings with a venation resembling that of the Leptidce ; the first posterior cell is always open, and the anal cell always closed, but the fourth posterior cell may be either closed or open.