20 



MOSQUITO ERADICATION 



surface and forms a trough in which the delicate piercing lancets lie 

 and by which they are protected from harm. 



"The lancets consist of six parts. The upper is a compound struc- 

 ture, representing the labrum or upper lip and the epipharynx of the 

 chewing insect. The epipharynx is grooved length-wise of its lower 

 surface in such a fashion as to form a complete tube when the hypo- 

 pharynx is laid against it from below. The hypopharynx is a slender, 

 flattened piece that fits closely against the open groove of the epipharynx. 

 Through the tube thus formed, the victim's blood is drawn into the 

 mosquito's digestive tract. The next pair of lancets are slender sharp- 

 pointed rods, which correspond to the mandibles or primary jaws of 

 chewing insects. The next pair of lancets, which correspond to the 

 maxillae or secondary jaws of chewing insects, are slender and pointed, 

 but have slightly enlarged barbed ends. 



Fig. 14. — Mosquito in the act of sucking blood, the stilette bundle being 

 free from the sheath, except at the distal end of the sheath. {After 

 Bahr.) 



"Almost, if not quite, coincidently with the moment that the skin is 

 pierced, a small amount of saliva is injected through the epipharyngeal 

 groove into the wound, and suction begins very soon after that. The 

 pumping portion, the fore-intestine, regularly contracts and expands, 

 drawing the blood from the victim into the mosquito's body. Unless 

 disturbed, the creature will continue to feed until its abdomen is 

 distended almost to bursting." 



IDENTIFICATION OF MOSQUITOES 



Ability promptly to identify the various kinds of mosquitoes is 

 almost an absolute necessity for the director of an anti-mosquito 

 campaign. Not only do the methods to be used for their eradica- 

 tion depend upon the species, but a knowledge of the particular 



