[Surra is generally stated to be transmitted by Stomoxys as well as Tabanus, and yet Nitzman in the Philippines obtained uniformly negative results in exhaustive experiments. Others have also been unsuccessful. Certainly Stomoxys can transmit the disease in French West Africa (Bonet and Roubaud), and mechanically has been proved to be capable of disseminating other trypanosomes (experimentally): sleeping sickness (T. gambiense); nagana (T. brucei); souma (T. cazalboui); and el debat (T. soudanense).
[S. calcitrans may also be a carrier of poliomyelitis (Rosenau and Brues, Harvard Alumni Bulletin, 1912, xv, No. 9, pp. 140–142). Several species are now known (S. brunnipes, Grünb.; S. inornata, Grünb.; S. nigra, Macq.; S. omega, Newst.; S. ochrosoma, Speiser, etc.).
Genus. Lyperosia, Rondani.
[A genus of small flies which bite man and animals, but are not so far connected with the transmission of any disease in man, but in Java it appears to carry surra (P. Schat, Meeledeel Praefstation Oost-Java, 1903, 3e ser., No. 44), the species being Lyperosia exigua, Meijere. These flies can be told from Stomoxys by the palpi being broader, flattened laterally, and as long, or nearly so, as the proboscis. When not feeding the palpi enclose the proboscis, as in Glossina. They are usually about half the size of Stomoxys, and are the smallest blood-sucking Muscidæ. They frequently swarm around and upon domesticated animals.
[The life-history of the horn fly in America (L. irritans, Linn.) is well known. It lays its ova singly in freshly dropped cow-dung, and there the maggots feed, pupating in the soil beneath.
[Patton and Cragg also give some details as to the life-history of Liperosia exigua (“Medical Entomology,” p. 375) as follows: “L. exigua, whose habits have been observed in Madras, usually lays twelve eggs at a time. The flies immediately return to the cow and the process is repeated when the dung is again dropped. The larvæ migrate from the dung when about to pupate, and the puparia are always found in the earth at some distance away or under the sides of the patch of dung. The fly usually hatches out in five days, though sometimes as late as the eighth. Weiss has studied the life-history of irritans var. weisii from Algeria; its larval stage lasts five days, and the flies hatch out of the puparia in another five days.”
[The other biting genera of Muscidæ, Hæmatobia, Hæmatobosca, Bdellolarynx, Stygeromyia, and Philæmatomyia, although sometimes annoying to man, have not in any way been connected with any disease.
[The horse fly (Hæmatobia irritans, L.[427]) attacks cattle chiefly, but now and then man is bitten. The different species can be told from Stomoxys by the palpi being nearly as long as the proboscis.
[The genus Philæmatomyia, Austen, is intermediate between Stomoxys and Musca in structure, and between the non-blood-sucking Musca, as M. domestica, and the blood-sucking Musca pattoni, Austen, which feeds on the blood exuding from the bites of true blood-suckers. They occur in Central Africa and India, Ceylon and Cyprus (vide “The Life-history of Philæmatomyia insignis, Austen,” Ann. Trop. Med. and Par., 1912, v, p. 515).
[Two flies belonging to the family Anthomyidæ also attack man, namely:—