Nc 6. DEPARTMENT OF AGRICULTURE. 333 



siirafce freqiiciitly to breathe and it is probable that they imist 

 come to the surface at least once a minute to get air. This is an 

 ini[)orlant point to remember. when melhods of destroying them are 

 discussed. The malaria carrying species has spotted wings, and 

 when at rest, the attitude of the body is all in one line, while the 

 common species are more or less angular or humijed. The spotted 

 winged species when resting on a wall, usually carries the body at 

 an a«gle from the wall while the body of the non-malarial kind is 

 carried parallel to the surface on which it rests. The hum of the 

 two kinds is also different and can be readily told from the tcoe 

 alone. TI\e note of the harmless kind is high pitched, while that of 

 the malaria carrying species is several tones lower. The mosquito 

 is mostly nocturnal and it is necessary to protect ourselves at night 

 by appropriate screens and by mosquito netting. The coly practical 

 melhods of destroying these pests on a large scale are to fill up or 

 drain their breeding places and to use kerosene co the surface of the 

 water. If kerosene is flowed on water in the quantity of one ounce 

 to fifteen square feet of water surface, it will kill the females as 

 they strike the water to lay their eggs and it will kill any of the 

 young as they come to the surface of the water to breathe. 



It is iiecessary for the people as a whole to recognize the vital 

 importance of these discoveries and to take concerted and intelli- 

 gent action for their own protection, and the writer predicts that 

 the day is not far distant when these diseases of man and also others 

 affecting the lower animals will be materially lessened or even wiped 

 out of existence. Economic entomology will also teach .the farmer 

 how to protect himself against the man^^ species of insects injurious 

 to vegetation even though at the present time he may not know 

 what scientific research is actually accomplishing for his benefit. 

 Knowledge is of slow growth and even slower in receiving proper 

 recognition. As we have shown, it was more than twenty-two hun- 

 dred years before humanity understood the real science of life as op- 

 posed to spontaneous generation, but in these times of universal 

 education, knowledge is appropriated more rapidly and is being 

 properly utilized for man's benefit. 



