206 TROPICAL MEDICINE AND HYGIENE 



myiasis. Further observations on intestinal myiasis in 

 the Tropics are required. 



DERMAL MYIASIS. 



In most cases of myiasis the flies have alternative 

 methods of development, and a warm-blooded host is not 

 essential for the life of the larva. In the CEstridce the 

 larva can only develop in such a host and are neces- 

 sarily parasitic. A few may infest man, though their 

 natural hosts are other animals. In Algeria (Estris ovis 

 is to be found in man, but is not very common. 



FIG. 83. Cordylobia larva from the skin of man, South Atrica. 3/1. 

 (After Blanchard.) 



The best known fly which deposits larvae under the 

 skin is the Dermatobia cyaniventris which is common on 

 the eastern coast of Tropical America and in the West 

 Indies. The larvae are known by many names, 

 " mosquito worm " and " ver macaque " being the most 

 used (fig. 81). The larvae are found singly in raised 

 cutaneous swellings, usually on some uncovered part 

 of the body. There is always a distinct opening from 

 which black fluid exudes when the larva is nearly 

 mature. 



In Tropical Africa similar tumours are found due to 

 the larvae of a different class of fly. These larvae are 

 known as the "ver du Cayor," " tumba fly" (fig. 77), 

 &c. The larvae are not uncommon in Europeans and 

 the tumours are usually in some part of the body covered 

 by clothing. 



The fly is the Cordylobia anthropophaga. It does not 



