514 



FLY MAGGOTS AND MYIASIS 



htei;,*- 



violet blue. The mouthparts are not fitted for piercing flesh, 

 and there is no " stinger " at the posterior end of the body to 

 drill a hole for depositing the eggs. Evidently, therefore, the 

 many accounts which one can find of the fly's biting or sting- 

 ing at the time the eggs are deposited are faulty. 



The manner in which the larvEe gain access to the skin of their 

 hosts is at present a much-disputed question. A recently ad- 

 vanced theory, and one which is looked upon with much favor 

 by many scientists is that the female fly captures a certain species 

 of mosquito, glues her eggs to the under side of the abdomen 



of this insect (see Fig. 206), and 

 trusts it to carry the eggs to the 

 body of some animal on which 

 it feeds. The eggs adhere to the 

 body of this animal- and hatch 

 almost immediately into tiny 

 maggots which at once bore 

 under the skin. For a discussion 

 of the origin and details of the 

 mosquito transmission theory 

 and objections to it, the reader 

 is referred to Chap. XXV, p. 451. 

 Other theories are that the fly 

 deposits its eggs, ready to hatch, 

 directly on the skin; on clothing 

 while not being worn, as does 

 the African skin maggot fly; or 

 on foliage along paths where 

 passing animals are hkely to 

 brush against the leaves. It is possible that, as is the case with 

 some other botflies, different methods of disposing of the eggs 

 may be used according to circumstances. 



However the larvee may reach their host, they immediately 

 enter the skin, probably through a pore, and begin their growth, 

 ultimately reaching a length of half or three-quarters of an inch 

 (Fig. 246). The anterior end of the larva is broad and is pro- 

 vided with double rows of thorn-shaped spines; the posterior end 

 is constricted, especially in fully-developed larvae, and does not 

 possess spines. As the larva develops, a sort of boil or cyst forms 

 about it, opening to the surface of the skin by a little pore. This 



Fig. 246. South American skin mag- 

 got, Dermatobia hominis; A, dorsal 

 view, extended; B, ventral view. X 

 about 3. (After Neiva.) 



