STRUCTURE 



427 



lying in a groove in the fleshy lower lip, which was the only part 

 visible before dissection. In the female mosquito there are six 

 of these needle-like organs the nature and names of which are 

 shown in Fig. 191. The " labrum-epipharynx " and " hypo- 

 pharynx " act together to form a tube for drawing up blood into 

 the mouth. A tiny tube runs down through the hypopharynx, 

 opening at its tip, through which saliva is poured into the wound 

 as through a hypodermic needle to prevent blood from coagu- 

 lating. The ensheathing lower lip does not itself penetrate the 

 wound, but bows back as the mosquito bites, the flexible tip or 



eye 



lab. 



palp/ 



FIG. 191. Side view of head of female Anopheles showing mouthparts; ant., 

 antennae; clyp., clypeus; ceph. s., cephalic scales; hyp., hypopharynx; lab., 

 labium; label., labellum; labr. ep., labrum-epipharynx; mand.; mandibles; max., 

 maxillae; palp., maxillary palpi. X 20. (After Nuttall and Shipley.) 



" labella " acting as a guide for the piercing organs as they are 

 sunk into the flesh. In male mosquitoes the piercing organs are 

 much degenerated, only the suctorial part of the apparatus being 

 well developed. 



Besides the variations of the parts mentioned already, mos- 

 quitoes vary as regards the form, distribution, color and other 

 characteristics of the scales which clothe much of the body and the 

 edges and veins of the wings; the details of the male reproductive 

 organs at the tip of the abdomen; the relative length of parts of 

 the leg; and in other respects. 



All mosquitoes have good " capacity " as far as the digestive 

 tract is concerned, having three food reservoirs connected with the 



