INSECTS INJURIOUS TO MAN AND IN HOUSEHOLD 645 



drain-pipes on houses and, in fact, any standing water which 



will remain for as much as a 

 week. It is usually necessary to 

 supplement drainage with oiling. 



In several states expensive 

 drainage operations have re- 

 claimed thousands of acres of 

 land which was useless. These 

 operations are usually under 

 state direction and at state ex- 

 pense, at least in part. 



The use of chemicals in the 

 water is still in the experi- 

 mental stage. 



Mosquitoes, in the north, usu- 

 ally winter as adults. There are 

 several generations in a season, a 

 generation requiring in warm 



weather less than two weeks and 

 FIG. 565. Culex solhcitans. (After . 



Smith, Report on Mosquitoes of New m cooler weather somewhat 



Jersey). longer. 



The accompanying illustrations will take the place of descriptions. 



Fleas* 



The flea is a third insect which has, within the very recent past 

 been transferred from the list of innocuous pests and placed 

 with the dangerous insect enemies of man. While it is true that 

 some common species have not yet been proven to be specific 

 bearers of disease it is now known that one, the rat-flea 

 (Xenopsylla cheopsis) has been pretty definitely proven to be the 

 usual, if not the only, means of transmission of the plague or 

 bubonic fever. This fact puts all fleas under suspicion and makes 

 them even less tolerable under civilized conditions than before. 



Fleas that affect man, in the more enlightened portions of the 

 world, are more or less accidental visitors from domestic animals, 

 usually cats and dogs. There are several species, the more 

 important being the human flea (Pulex irritans). and the cat and 



* Order Siphonaptera. 



