452 MOSQUITOES 



cones of Caracas, the mosquito is utilized by the Dermatobia fly 

 as an aeroplane for transporting her eggs or larvae to a suitable 

 host for development, and we would have here, if true, one of 

 the strangest interrelations of animals in the whole realm of 

 nature, comparable, perhaps, with the manner in which certain 

 mites of the family Tyroglyphidse assume a special traveling garb 

 and adhere to the appendages of flies to obtain transportation 

 to new feeding grounds (see pp. 339-340). 



Dr. Neiva, of the Instituto Oswaldo Cruz, Brazil, does not 

 believe in the mosquito theory. He points out that in various 

 parts of tropical America not only mosquitoes, but also craneflies, 

 ichneumon-flies, certain large hairy flies and other insects are 

 accused of being Dermatobia carriers, though they could not 

 possibly serve in this capacity; that although Dermatobia is 

 abundant throughout Brazil, and the mosquito Janthinosoma 

 lutzi, on which the eggs are found, also occurs there, yet no 

 specimen of this mosquito with these eggs has ever been found 

 there in spite of the great amount of mosquito collecting which 

 has been done in Brazil; that the observations of Dr. Tovar must 

 be at fault, since all observations on the development of the 

 larva are opposed to the possibility of an eleven-days-old specimen 

 being able to mature; that the eggs from a Janthinosoma figured 

 by Dr. Surcouf do not agree with the eggs obtained by dis- 

 secting adult female flies; that the fly is frequently seen pestering 

 cattle and horses, and that he himself has been persistently fol- 

 lowed by egg-containing females; that new-born children kept 

 indoors are very seldom infected, although the incriminated 

 mosquitoes, but not the flies, are common in houses; and that 

 dissected flies show the eggs to be in various states of develop- 

 ment, indicating their disposal singly or a very few at a time, at 

 intervals. Neiva's contentions are further corroborated by the 

 fact that the mosquito theory is upheld by other observations, 

 so obviously inaccurate as to tempt one to look with doubt on 

 all of them. Dr. Zepeda, of Nicaragua, for instance (quoted by 

 Sambon), says he observed Dermatobia tumors developed two 

 days after bites by egg-bearing mosquitoes, and says that seven 

 days later the larva dropped out! Sambon believes that the 

 larvae of some other fly were confused with those of Dermatobia, 

 especially as Zepeda later obtained specimens of the screw-worm 

 from tumors following mosquito bites. 



