400 GENERAL SCIENCE 



two rows side by side, the eggs standing on end, while 

 the Anopheles lays its eggs singly and not in groups. 

 The body of the adult Culex is in a horizontal position 

 when at rest, while the body of the Anopheles is 

 almost vertical when at rest. The yellow fever mosquito, 

 or the Stegomyia, carries the yellow fever germ much the 

 same as the Anopheles carries the malaria germ. It 

 secures a meal from a person who has the yellow fever. It 

 takes the yellow fever germ into its body and is then able 

 to transmit those germs into the bodies of persons who do 

 not have the disease. Yellow fever used to be very com- 

 mon in our Southern states and in the Panama Canal 

 zone; but the destruction of the mosquito in these regions 

 has almost eliminated the disease. There are three 

 methods which are used for the destruction of the mos- 

 quito, (i) Keep the water in swamps and streams 

 covered with oil so that the larvae cannot breathe. 

 (2) Drain the swamps wherever possible so that the 

 mosquito cannot find a favorable place for depositing its 

 eggs. (3) Keep the water stocked with fish which eat 

 the larvae of the mosquitoes. 



276. The Rat and Flea. The rat is a native of China 

 and has moved westward over the Asiatic and European 

 continents. It came to the United States in 1775, and 

 in 75 years worked its way across North America to San 

 Francisco. It was definitely learned in 1907 that the 

 rat carries a very destructive disease. This disease 

 almost depopulated many cities in Europe during the 

 past centuries; the cause of the disease was not known 

 at that time. Many superstitious people thought that 

 it was a plague visited upon the people by God for their 

 sins. The disease is known as the Bubonic plague or 

 Black Death, and about 95 per cent of those who 



