42 



ARTHKOPODA 



boscis, head, thorax, 

 and abdomen of Ano- 

 pheles are all in a 

 straight line, and the 

 body is held oblique 

 to the surface to which 

 the insect adheres, 

 apparently trying to 

 stand on its head. 

 Members of the genus 

 Culex have a bend at 

 the juncture of the 

 abdomen and thorax 

 and hold the body par- 

 allel with the surface 

 to which they cling. 

 Agents of Disease. About the year 1899 it was clearly 

 shown that the several species of Anopheles are the agents 



FIG. 17. Photograph of Anopheles, the agent 

 transmitting malaria. The antenna? are curved 

 and the upper two of the three straight projec- 

 tions from the head are the palpi. Enlarged 

 three diameters. 



FIG. 18. Diagrammatic vertical section of the head and proboscis of a mosquito. 

 I, labium bent as when the other parts pierce the skin ; p. pumping organ ; o, 

 hypopharynx through which is a channel for the exit of the secretions of the 

 poison and salivary glands pn and s ; d, exit for poison and saliva ; m, maxilla ; 

 ma, mandible ; la, labrurn below which is the channel conducting the food from 

 the inlet at n ; st, stomach. Drawing by Reese. 



in transmitting the malaria from man to man. When the 

 mosquito feeds on the blood of a malaria patient thou- 



