It is probable that infestation usually occurs through eating partially decayed fruit or vegetables on which the flies have deposited their eggs. Wellman points out that the flies may deposit their eggs in or about the anus of persons using outside privies and Hewitt believes that this latter method of infection is probably the common one in the case of infants belonging to careless mothers. "Such infants are sometimes left about in an exposed and not very clean condition, in consequence of which flies are readily attracted to them and deposit their eggs." [Illustration: 101. Larva of Fannia scalaris.] MUSCINÆ--The larvæ of the common house-fly, _Musca domestica_, are occasionally recorded as having been passed with the feces or vomit of man. While such cases may occur, it is probable that in most instances similar appearing larvæ of other insects have been mistakenly identified. _Muscina stabulans_ is regarded by Portschinsky (1913) as responsible for many of the cases of intestinal myasis attributed to other species. He records the case of a peasant who suffered from pains in the lower part of the breast and intestines, and whose stools were mixed with blood. From November until March he had felt particularly ill, being troubled with nausea and vomiting in addition to the pain in his intestines. In March, his physician prescribed injections of a concentrated solution of tannin, which resulted in the expulsion of fifty living larvæ of _Muscina stabulans_. Thereafter the patient felt much better, although he suffered from intestinal catarrh in a less severe form. [Illustration: 102 Muscina stabulans (×4). After Graham-Smith.] CALLIPHORINÆ--Closely related to the Sarcophagidæ are the _Calliphorinæ_, to which group belong many of the so-called "blue bottle" flies. Their larvæ feed upon dead animals, and upon fresh and cooked meat. Those of _Protocalliphora_, already mentioned, are ectoparasitic on living nestling birds. Larva of _Lucilia_, we have taken from tumors on living turtles. To this sub-family belongs also _Aucheromyia luteola_, the Congo floor maggot. Some of these, and at least the last mentioned, are confirmed, rather than faculative parasites. Various species of Calliphorinæ are occasionally met with as facultative parasites of man. [Illustration: 103. Lucilia cæsar, (×3). After Howard.]