32 AGRICULTURAL EXPERIMENT STATION. 



introduced into the wound first, and the blood is sucked in after- 

 ward. If, as rarely happens, the covering- strip is separated from 

 the groove, six parts or lancets seem to be present. The usual 

 appearance is five; the two central parts counting as one. The 

 lateral lancets make two pairs, one of them very slender, except 

 at the tip where there is a slight enlargement and a series of 

 teeth; the other more flattened and blade-like with a lancet-like 

 tip which may or may not have a slightly toothed edge. These 

 lancets with the beak in which they run form the maxilla or 

 second jaws of the insect and they are all connected at the base. 

 They are purely surgical structures, meant for puncturing and 

 •cutting and have nothing to do with the actual feeding. The 



Figure 8. 



Salivary glands of Culex at right, Anopheles at left; greatly enlarged. 

 THoward's "Mosquitoes," by permission.) 



(From 



-central structures represent the labium or lower lip and they end 

 at the base in the mentum which forms a sort of sucking pump 

 leading into the oesophagus or throat. Just below the base, where 

 the covering structure or epipharynx or palate takes its origin, 

 the tube from the salivary glands has its opening. All of these 

 structures in their proper relation to each other are shown at 

 figure 7, in which each of the parts are named. 



The salivary glands lie in the thorax just back of the neck and 

 ■can be dissected out with infinite difficulty only. There is one set 

 of glands on each side and these consist of a central part or bulb, 

 Avhich serves as a reservoir for the product or saliva and one or 



