192 SANITARY ENTOMOLOGY 



ing species have been recorded in this connection: Eristalis tenax Lin- 

 naeus, E. arbustorum Fabricius, E. dimidiatus Wiedemann, and Heloph- 

 ilus pendulinus Meigen. 



The cheese maggot or skipper Piophila casei Linnaeus, is referred 

 to in a number of instances as the cause of intestinal myiasis, often pro- 

 ducing intense colic, and this form has also been recorded from the nose. 

 On account of the common habit of this fly of depositing its eggs in 

 cheese and smoked meat, it is no doubt often eaten in considerable num- 

 bers and the cases where it gives trouble must be comparatively few. 

 This insect passes its complete life cycle in the foods mentioned above, 

 usually attaining the adult stage in about three weeks. It is world-wide 

 in distribution. 



Species of Muscina, especially M. stabidans Macquart, have been met 

 with frequently in cases of intestinal myiasis, especially in Europe. 



Mydaa vomiturationis Robineau-Desvoidy is charged with a case of 

 fatal intestinal myiasis. 



Hydrotaea meteorica Linnaeus, a fly probably normally predaceous in 

 the larval stage, has been found to produce intestinal myiasis, in which 

 case blood is sometimes passed accompanied with severe pain. 



Larvae of the common house fly have been passed in living condition, 

 sometimes preceded by pain. Most of these cases have been in infants 

 and the larvae no doubt usually gain access through the anus. These 

 cases usually result from improper care. 



The cluster fly, Pollenia rudis Robineau-Desvoidy of the family 

 Muscidse, has been reported in a case of intestinal myiasis. It is difficult 

 to see how this form could gain access to the human alimentary tract since 

 it is normally found only as a parasite of earthworms. 



In certain parts of tropical America and the West Indies, India, Cey- 

 lon, and the Malay States, the small Phorid, Aphiochaeta ferruginea 

 Brunetti, has been found infesting the human intestinal canal in many 

 instances. Brunetti states that specimens of this fly were sent to the 

 Indian Museum by Crombe with a statement that "eggs, grubs, and flies 

 were all voided together." This occurrence, together with observations 

 made by Baker and reported by Austen, indicate that the flies are capable 

 of living and depositing eggs in the human intestines. This is also sub- 

 stantiated by the fact that larvae of this fly may be passed with excre- 

 ment for as long as a year with symptoms similar to those of beri-beri. 

 Other members of the family Phoridae have been found in human corpses 

 buried for two or more years ; living larva-, pupae, and adult flies being 

 found together. Aphiochaeta ferrugmea breeds in excrement and often 

 frequents various foods including fresh meat. It also breeds in carrion. 

 Its small size enables it to pass through ordinary screen wire and thus 

 increases its potentialities for producing disease. 



