Systematic Position and Structure 7 



which he says does not take place when saliva alone 

 is introduced, in like manner, into the tissues of a 

 human being. He also denies to saliva the anti- 

 bloodclotting function with which it has already 

 been credited, attributing whatever non-coagulability 

 exists in the fluid at the site of puncture to the 

 action of the carbon dioxide expelled from the 

 diverticulae, during the act of biting. He says, in 

 substance, that the molds, together with the gas 

 bubbles and saliva infused, may be withdrawn almost 

 completely by the capillary attraction of the epi- 

 pharynx, aided by the state of negative pressure 

 which exists in the cavity of the proboscis at the 

 end of the abdominal contraction (which forces out 

 the saliva), thence the aforesaid mixture of molds, 

 etc., may be sent by the conjoint action of esopha- 

 geal peristalsis (contractions of the esophagus) and 

 the abdominal action, into the mid-gut (stomach) 

 where they thrive and multiply. This state- 

 ment furnishes a scientific basis for the widespread 

 belief that no ill effects ensue from a bite, provided 

 the mosquito is allowed to finish its meal. 



On each side of the base of the beak are placed 

 the palpi. These are jointed structures, generally 

 long in the males, extending to or beyond the tip of 

 the beak and thickened at their outer ends. They 

 are, as a rule, short in the females. 



The antennae are elongated, jointed appendages, 

 situated just above the beak, which is usually longer 

 than these organs. The first joint is socket like, 

 the other joints are, in the female, cylindrical and 

 whorled with a few long hairs ; in the male they are 



