(Figures 5-49 and 5-50)
The Brachycera, horse flies and deer flies, are large and viscious day time biters that are found throughout the world. Genera include Tabanus (Fig. 5-49),Haemtopota, Silvius, Hybomitra, Diachlorus and Chrysops (Fig. 5-50). Like the Nematocera, only the female fly feeds on blood. The female lays eggs neer foliage overhanging water or at the waters egdes. The larva enters the water where. In some species, the larvae feed on organic debris while others are predators. Larvae may remain active a year before they pupate. The pupa occurs in drier soil, and after one to two weeks the adult fly emerges. The adult flies are large, up to two inches in length, and cause significant lesions at the site of the bite. The major biting activity is likely to occur during the heat of mid-day. Some humans react significantly to the bites and develop large swellings that may be for or five inches in diameter. It is to be expected that cats are also plagued by the bites of these flies, but specific cases have not been described.
Figure 5-49. Tabanus. Lateral view of an adult; note the shape of the antennae.
Figure 5-50. Chrysops. Dorsal view of an acult female; note the mottled appearance to the wings and the triangular shpae of flies of this genus due to the way the wings are held when at rest.