24 



AMERICAN MUSEUM GUIDE LEAFLETS 



of facets distributed over a spheroidal surface makes it possible for the 

 mosquito to see in almost every direction. 



In front of the eyes are the antenna', two slender organs, with a cen- 

 tral jointed axis of 15 or l(i segments, each hearing a whorl of hue hairs. 

 The antennae are organs of hearing, and by means of them the male is 

 Antennae a '"' e to (letect t,ie presence of the female. If the "song" of 

 a female mosquito he imitated with a tuning fork, the 

 antennae of the male mosquito, which support long and exceedingly 

 delicate whorls of hairs (Fig. 1 I, that respond to every vibration of the 

 air, may he seen to bend in the direction from which the sound proceeds.' 



Below the antenna-, at the very front of the head, are the mouth-parts, 



P0STEftl0Ri'<T50PWAGEAI 





FIG. 18. HEAD OF FEMALE MALARIA MOSQUITO. 



constituting the so-called "proboscis" (Fig. 17). This consists of sev- 



_ , . eral members. The principal one, lying above all the other 



Proboscis -iii 



of Female mouth-parts, is the labrum, deeply grooved along its 



lower side.-' Under the labrum there is a delicate chitinous 



lamella, the "hypopharynx." The hypopharynx is closely applied to 



the labrum along its entire extent, and by closing the groove therein 



from below, forms therewith the tube through which the mosquito sucks 



up blood or other liquid food 'Fig. 19). A Hue tubular channel which 



runs along the median line of the hypopharynx serves to conduct the 



poison that the mosquito pours into the wound when sucking blood. 



Along the sides and below the tube, composed of these two mouth-parts, 



there are two pairs of very slender chitinous rods, expanded at the ends 



into lancet-like blades set with fine teeth. One pair, the "mandibles," 



are exceedingly delicate; the other, the "maxillae," are stouter and have 



'Mayer, A. M. Researches in Acoustics. Am. Jour. Sci. and Arts. III. viii. p. 

 81. is; l. 



2 The "labrum" is undoubtedly a compound structure and properly is the "labrum- 

 epipharynx." 



