224 



DISEASES DUE TO PROTOZOA 



This gland is connected with the biting apparatus, 

 and some of its secretion is left under the skin when 

 the mosquito bites and sucks blood. It is probably the 

 secretion from this gland which causes the itching 

 of the ordinary mosquito bite. This reproduction in 

 the mosquito requires seven to ten days. When a 



FIG. 07. Body of Culex (a) when resting is held parallel to wall 

 in a curved position, that of Anopheles (b) at an angle of about 45 

 degrees and is straight; wings of Culex (c) are generally not spotted; 

 those of Anopheles (d) are spotted. (From Kolle and Hetsch.) 



person is bitten the parasites, left under the skin, 

 penetrate their cell of choice, the red blood corpuscle. 

 In the body of this cell they have the power of under- 

 going an asexual division (see Fig. 64). The minute 

 form swells into a large body and breaks up into small 

 spores. When this mass of young forms hasjreached 

 a size too great for the red cell the latter bursts, syn- 



