44 



THE POPULAR SCIENCE MONTHLY 



he has killed over 40,000 flies (about four quarts) inside of twenty- 

 four hours in a barn where flies were very numerous. 



Other Flies that Carry Diseases 

 The terrible scourge of Africa known as sleeping sickness is caused 

 by a protozoan parasite known as Trypanosoma gambiense, and is 

 transmitted by the bite of a species of fly, Glossina palpalis. In our 

 own southern states the disease known as " pink eye " is disseminated 

 by a minute fly of the genus Hippelates. 



View op an Ill-kept City Stable Yard, showing a manure heap where thousands 



of house flies breed. 



Mosquitoes and Malaria 



Malaria has been known ever since 400 B.C. in southern Europe, 13 

 and from the records it must have been present in Connecticut for 

 about 250 years, though rot generally distributed here, nor did it ap- 

 pear in the form of an epidemic until about 1860, when it broke out 

 in the southwestern corner of the state and spread gradually during 

 the next twenty years until the entire area of the state was involved. 

 It is thought that soldiers returning from the Civil War brought it 

 from the south. 



The cause of malaria was formerly thought to be gases or foul 

 emanations from swamps, and it was in 1881 that Laveran, a French 

 army surgeon, discovered in the red corpuscles of human blood a pro- 

 tozoan parasite, which he named Plasmodium malaria. Though the 

 mosquito was suggested by King in 1882 as a possible agent in trans- 



13 L. O. Howard, Bureau of Entomology, Bull. 78, p. 37. 



