There is another fly in Mexico which is dangerous to man; it is known by the name of _Musca hominivora_, or more correctly, _Lucilia hominivora_. Vercammer, a military surgeon of the Belgian army, relates that a soldier in Mexico had his glottis destroyed, and the sides and the roof of his mouth rendered ragged and torn, as if a cutting punch had been driven into those organs. This soldier threw 120 up with his spittle more than two hundred larvæ of this fly. We give below the figure of the larva and of the perfect insect. He had found this man sick in Michoacan, at a height of 1,866 metres, between Mexico and Morelia. [Illustration: Fig. 9.--Lucilia hominivora.] [Illustration: Fig. 10.--Lucilia hominivora, larva.] My son-in-law, Dr. Vanlair, informs me that citric acid or the juice of lemons is efficacious in destroying these insects. Injections of this acid are thrown into the nasal fossæ. At Brazil, in the province of Minas Geraes, they give the name of _Berne_ to a fly which attacks man and cattle from the month of November until February. It deposits its eggs in the loins, the arms, the legs, or even the scrotum, without the victims perceiving it, and their presence is first shown by a redness, then by a sensation of itching, and a swelling with the formation of pus. Among those insects which suck the blood, is one which is known by every one, the Breeze-fly, _Tabanus bovinus_. Happily it seldom attacks any animals except oxen and cows. We give a representation of the insect, the parts of the mouth, and one of the antennæ. In the same order of diptera are found ordinary flies, among which may be easily distinguished the three species which are here represented, 121 and which differ as much by their external characters as by their mode of life. [Illustration: Fig. 11.--Ox-fly.] [Illustration: Fig. 12.--Antenna of Ox-fly.] [Illustration: 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 122 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. [Illustration: Fig. 14.--Flesh Fly.] [Illustration: Fig. 15.--House Fly.]