510 ON THE DEVELOPMENT OF DERMATOBIA HOMINIS. 



in mammals. He speaks particularly of "les grosses larves qui se trouvent dans la 

 peau mammelonnee qui garnit la tete et le cou du Dindon et de quelques autres vola- 

 tiles." This possibility has passed unnoted by later writers and finds its confirmation 

 in the observations recorded here in which the species was found as a parasite in two 

 other birds. It occurs thus in birds both under natural conditions and in domesti- 

 cation. 



In man it has been reported from various regions of the body, namely, head, 

 arm, back, abdomen, scrotum, buttocks, thigh, axilla; and the adult fly appears 

 consequently to depend upon opportunity rather than choice of definite location 

 in oviposition. 



A veritable plague to cattle in those regions where it exists, its more occasional 

 presence in the human host is, on the testimony of many sufferers, accompanied by 

 excruciating pains, especially at times when the larva is moving; the early morning 

 and evening hours appear to be those in which the pain is most severely felt. Most 

 authors believe it is doubtful if it reaches full development in man, and in no case on 

 record has the adult been developed from any larva taken from human flesh. Yet 

 Magalhaes (quoted by Blanchard, '92, p. 145) obtained four which were old, one of 

 them indeed very dark brown and immobile, so that he thought it had begun to pupate, 

 constrained by circumstances from leaving as usual its larval seat. 



3. Geographical Distribution. The species enjoys a wide range on this conti- 

 nent. It is common in Brazil, extending at least to 18 south latitude and west to 

 the mountains. Cases are recorded from French and British Guiana, Venezuela, 

 and the island of Trinidad. In Colombia it appears to be frequent, and in his last 

 paper Blanchard ('97, p. 647, note) refers to a record of its presence in Peru, that is, 

 west of the great chain of the Cordilleras, where one of the earliest of reports (C. 

 Linnaeus, Jr.) had also located it. Its discovery in intervening territory in South 

 America with suitable climatic conditions is thus evidently only a matter of 

 attention. 



Farther northward previous records of this species are at hand from Costa Rica, 

 Honduras, Guatemala, and from the Mexican States Yucatan, Tabasco, Vera Cruz, 

 and many others even as far north, if the determination of the parasite is correct, as 

 Tamaulipas and Sinaloa, about 25 north latitude, where it is signalized, according 

 to Altamirano. Blanchard, who records this, says that if the localities are correct 

 the Dermatobia occurs to the westward of the great Rocky Mountains, on the Pacific 

 slope. Its presence on this slope is placed beyond all doubt by the confirmatory 

 evidence of this paper, as the specimens were taken well down; below the forests'on the 

 coastal plain itself. Blanchard adds that it does not occur in the great central plateau 



