THE ANATOMY OF THE ADULT MOSQUITO 97 



of the latter make it probable that the function of this 

 thickening which fills up the greater part of the chitinous 

 sphere, is connected with the sense of taste. The anterior 

 part of the lining membrane, especially below, is closely 

 armed with minute spines, the back of the cavity being 

 lined with the soft tissues of what is evidently a nervous 

 end organ, and is probably that of taste. 



At the point where it springs from the cup-like expansion, 

 the pharyngeal tube is somewhat constricted, but after this 



Fig. 23. — Transverse Section of the Head of An. Culicifacics, sp. n. 

 X 120 diams. , showing the pharyngeal bulb, with its dilator muscles. Imme- 

 diately above is seen the mass of the brain, or supra-CESophageal ganglia ; 

 /, salivary duct ; g, ventral nerve cords ; n, pharyngeal bulb ; q, tracheae. 



it runs for a short distance as a tube of uniform thickness, 

 through the mass of the oesophageal nerve collar, and then 

 expands into a fusiform dilatation of considerable size. As 

 usually seen (in fig. D) it is longitudinally furrowed so that 

 its transverse section would have the outline of a wallflower, 

 but when filled by imbibition of glycerine these infoldings 

 disappear. 



This bulb unquestionably serves as the pump, by means 

 of which the insect draws up the fluids of the tissues into 

 which its proboscis is plunged ; as it is provided with a 

 7 



