INSECTS INJURIOUS TO MAN AND IN HOUSEHOLD 641 



Mosquitoes * 



Mosquitoes, like house flies, have long been known as nuisances, 

 almost intolerable in certain locations, but it is only within the 

 last quarter of a century that 

 their disease-carrying possibil- 

 ities became known. It has 

 been determined in that time 

 that they are the sole means 

 of the transmission of malarial 

 fever and of yellow fever from 

 man to man, that they trans- 

 mit also certain tropical dis- 

 eases, and that there are strong 

 probabilities of their being im- 

 plicated in the transmission of 

 other diseases. 

 Malarial fever is transmitted 



FIG. 556. The house mosquito; Cukx 

 pipiens. After J. B. Smith, New Jer- 

 sey Agr. Expt. Sta. 



by mosquitoes belonging to the genus 

 Anopheles, of which there are several 

 different species. It is caused by a 

 minute one-celled animal of the lowest 

 type, which resembles in many ways 

 the bacteria, but is entirely distinct 

 from them. This organism spends a 

 part of its cycle of development in the 

 body of the mosquito and a part in the 

 blood of man. Taken from man in 



FIG. 557.-Distinction be- the blood sucked U P b ^ the mosquito, 

 tween malarial and other it develops within the body of the mos- 

 mosquitoes. Resting po- qu i to , then makes its way to the sal- 

 sition of Culex above and . , , f ., .. . . . 



Anopheles below. After * var y g lands of the mosquito and is in- 

 Howard, U. S. Dept. of jected into the blood of the victims of 

 Agr * the mosquito when it bites. 



* Family Culicidae. See numerous publications, those of Dr. J. B. Smith, 

 from the New Jersey Exp. Sta., and of Dr. L. O. Howard of the Bureau 01 

 Entomology, U. S. Dept. of Agr., being most extensive. 



