MYIASIS— TYPES OF INJURY, LIFE HISTORY, HABITS 193 



The AnthomA'id flies of the genus Fannia have been recorded as caus- 

 ing serious gastric disorders. Among the symptoms are abdominal pains, 

 nausea, and vomiting, and sometimes vertigo, headache, and bloody diar- 

 rhea. Fannia canicularis (plate VII, fig. 3; text figs. 14-16), commonly 

 called the lesser house fly, and Fanma scalaris (text figs. 17-19) are 

 widely distributed and breed in various types of decaying vegetable mat- 

 ter and excrement. We find that the larvae will feed upon and penetrate 

 meat, and they may attack the living tissues to some extent. 



In the urogenital infesting group the above-mentioned species of 

 Fannia, which are also known as the latrine flies, figure most prominently. 

 These species are rather strongly attracted to human excrement, espe- 

 cially urine. This habit is undoubtedly responsible for the infestation 

 of the genitalia. Such infestations must certainly be attributed to the 

 exposure of the genitals in sleep by drunken or careless persons, or occa- 

 sionally infants. Robineau-Desvoidy has reported a case in which an 

 Oestrid larva was passed from the bladder by a woman. Kollar has re- 

 ported the occurrence of a large number of larvae of the common house 

 fly in the vagina of a diseased woman. Chevral has brought together 

 a number of records of cases of myiasis of the genitalia. 



Europe. — Nearly all the above-mentioned forms are to be encoun- 

 tered in parts of Europe. In the Mediterranean countries one would 

 expect to find a greater number of forms leading to these types of 

 myiasis. 



Africa. — Several of the previously mentioned forms occur in Africa. 

 The Oestrid larva, Pliaryngoholus africanus Brauer, commonly attaches 

 to the walls of the esophagus of the African elephant, and an Oestrid 

 of the genus Cobboldia (C loxodontis Brauer and C. chrysidiformis 

 Rodhain and Bequaert) are found in the stomach of the African ele- 

 phant, and C. elephantis (Steel) Cobbold, attacks the Indian elephant in 

 a similar way. Species of Girostigma in the same family infest the 

 stomach of the Rhinoceros. Anthomyia disgordiensis is said to be not 

 infrequently passed from the intestines of man in Angola. 



FORMS PRODUCING MYIASIS IN HEAD PASSAGES 



All of the species included in this group are normally parasitic on 

 animals, and infestation of man, altliough not uncommon, must be con- 

 sidered accidental. In the lower animals the attack of these larvag is 

 often quite injurious tliough not usually fatal in itself. In man the 

 principal injury sustained is in the eff'ects on the eye when it happens to 

 be attacked. 



America. — In the United States as well as in all parts of the world, 

 the sheep head maggot, Oestrus oris Linnaeus, is the most important 



