Brumpt cites a curious case of accidental parasitism by a coleopterous larva belonging to the genus _Necrobia_. This larva was extracted from a small tumor, several millimeters long, on the surface of the conjunctiva of the eye. The larvæ of this genus ordinarily live in decomposing flesh and cadavers. DIPTEROUS LARVÆ [Illustration: 99. Piophila casei. After Graham-Smith.] MYASIS--By this term (spelled also myiasis, and myiosis), is meant parasitism by dipterous larvæ. Such parasitism may be normal, as in the cases already described under the heading parasitic Diptera, or it may be facultative, due to free-living larvæ being accidentally introduced into wounds or the body-cavities of man. Of this latter type, there is a multitude of cases on record, relating to comparatively few species. The literature of the subject, like that relating to facultative parasitism in general, is unsatisfactory, for most of the determinations of species have been very loose. Indeed, so little has been known regarding the characteristics of the larvæ concerned that in many instances they could not be exactly determined. Fortunately, several workers have undertaken comparative studies along this line. The most comprehensive publication is that of Banks (1912), entitled "The structure of certain dipterous larvæ, with particular reference to those in human food." Without attempting an exhaustive list, we shall discuss here the more important species of Diptera whose larvæ are known to cause myasis, either external or internal. The following key will serve to determine those most likely to be encountered. The writers would be glad to examine specimens not readily identifiable, if accompanied by exact data relative to occurrence. _a._ Body more or less flattened, depressed; broadest in the middle, each segment with dorsal, lateral, and ventral fleshy processes, of which the laterals, at least, are more or less spiniferous (fig. 101). _Fannia_ (= _Homalomyia_). In _F. canicularis_ the dorsal processes are nearly as long as the laterals; in _F. scalaris_ the dorsal processes are short spinose tubercles. _aa._ Body cylindrical, or slender conical tapering toward the head; without fleshy lateral processes (fig. 105).