ARTHKOl'ODA 



217 



place the fleas (Fig. 221 ), although in the more extended classifi- 

 cation they occupy an order by themselves. They are wingless, 



FIG. 220. Plasmodium, the malaria parasite, 1-16, and Anopheles claviger, the mosquito, 

 17-22. For 1-16 see Fig. 16, page 36. 17, adult female malarial mosquito; head of male 

 below; 19, larva, 20, pupa; 21, stomach of mosquito showing tumors produced by the 

 developing oocysts of the parasite ; 22, cross section of salivary gland of mosquito, show- 

 ing in its cells sporozoites which have wandered in from the tumors of 21, and are now- 

 ready to pass into the blood with the bite of the mosquito. (After Leuckart-Chun's wall 

 chart, from Sedgwick's Sanitary Science. ) 



