The ((Estrus oris, L.) belongs to still another genus of (Estridx and differs again radically in habits. The adult flies are smaller than those of the other species mentioned and resemble large house-tlies. The color of the head and thorax is dull yellow, but so spotted with brown as to appear brownish. The abdomen is velvety and variegated with dark brown and straw-color. The fcmah• fly lays her eggs in the noses of sheep. They hatch almost immediately, and the larvi• at once commence. to work their way up the nostrils and the nasal passages, caus ing great irritation, until they reach the frontal sinuses, which are cavities located between the two plates of the skull, and lying one on each side of the central line of the head and between and a little above the eyes. Here they attach themselves to the membranes which line the sinuses. and feed upon the mucus. The damage caused by this insect has probably been under estimated. Stiles has found that in Colorado, in some large flocks, at least 25 per cent. of the animals are affected; and after conducting a number of post-mortems he is convinced that in many cases the hots cause the death of the animal. It is the custom in some places to pre pare 'salt logs' for the sheep to visit. The salt is placed in cavities in the log and the edges of the cavity are smeared with tar, so that the sheep in eating the salt gets a eertain amount of tar upon its nose. This is supposed to deter
the flies from Laying their eggs. A recent remedy proposed by Stiles consists in puncturing the frontal sinuses with a trochar and syringing in a small quantity of gasoline.
Other hot-flies affect domestic animals and in tropical regions even man himself. The (Estrus hominus of Linnaeus and the Dermatobia noxialis of Goudot, in Guiana, Mexico, and other tropi cal regions, lay their eggs upon the skin of monkeys and of human beings, and the la rvie form cysts under the skin. much like those of the ox-bot. The emasculating bot-fly ( Cutere bra emasculator, Fitch) lives in the larval state in the inguinal and axillary (testicles) of squirrels and gophers. The rabbit bot-fly (Puterehra eunieuli. Clark) in the larval stage forms a large tumor in the skin of the common rabbit. Other species affect reindeer in Europe, and deer, elk, and antelopes in Ameriea. The history of many .:1meri•an species, with il lustrations. may be found in Oshorn's Insects Affecting Domestic Animals (Bulletin No. 5, n.s., Div. of Entomology. I'. S. Dept. Agri., Washington, which also contains an tensive bibliography of the (Estrid:e.