52 DKAGON FLIES VS. MOSQUITOES. 



it and proceeded against as a distinct class, tlie problem 

 would be capable of solution. 



The obscurity of the facts having to do with human 

 parasitism and the difficulty of following the feeding 

 habits of the mosquito and fly in Xature make it very dif- 

 ficult to come to any definite conclusions. The medical 

 literature on this subject is too conflicting to guide the 

 student in forming a final judgment. 



The principal charges against Culex are as follows : 

 (1.) Its female is an unalloyed pest in the imago state, by 

 reason of its acquired fondness for human blood. (2.) It 

 is a harborer of Haematozose and consequently a constant 

 menace to man by virtue of the fact that, as host of these 

 dread enemies, it helps them towards a period of develop- 

 ment wdiere they become a serious visitant in the human 

 system. (3.) It is argued that if it can harbor and trans- 

 mit such diseases as arise from Filaria and other forms, it 

 may also be the means of inoculating with malaria and 

 other diseases. In other words, if Filaria sanguinis hom- 

 inis can be passed into Culex, the far smaller germs be- 

 lieved to be the prime cause of these other diseases can 

 easily be transmitted in the same way or by the more di- 

 rect method of inoculation by puncture with the proboscis. 



There is room for much useful research in this Filaria 

 problem. Our present knowledge may be epitomized as 

 follows : Lewis "^ has found twenty female mosquitoes out 

 of a hundred and forty to be infested with H?ematozoa ; 

 McLeod, commenting on this, states that the diseases aris- 

 ing from Filaria in the blood " are very serious." Man- 

 son ®^ estimates that the blood of one man may at one 

 time contain at least two million embryo Filarise. As 

 the individuals of such a brood could not attain any size 



