Fig. 12.—Antenna of Ox-fly.
Fig. 13.—Blue Fly.
Another fly also attacks horses and cattle, and occasionally even man, the Asilus crabroniformis, whose wounds sometimes draw blood. Martins, the birds of the twilight, which fly in flocks above the houses, describing circles and uttering shrill cries, are usually infested by many vermin, among which we find a fly of considerable size, which looks much like a spider, the Ornithomya hirundinis. It moves about among the
feathers with astonishing facility, and it is not always confined to the same bird; it quits its host to establish itself upon another, and sometimes throws itself upon man to suck his blood.
Fig. 14.—Flesh Fly.