THE ANATOMY OF THE ADULT MOSQUITO 



91 



ventral aspect devoid of any rigid sternal plate, being 

 composed entirely of elastic flexible membrane. The last 

 three, however, are shorter and diminish rapidly in width ; 

 and the last two are specially modified to accommodate the 

 apertures of the digestive and reproductive systems, the 

 anus being placed on the ventral aspect of the eighth 

 segment, while the tergum of the ninth is quite invisible 

 in the usual position of the insect, and all that can be seen 



Fig. 22. — Transverse Section through the Posterior Part op the 

 Abdomen of a Hibernating Female. 



dv, dorsal vessel ; jws, perivascular space ; ov, ovary ; r, rectum ; 

 VI, Malphigian tubes ; g, last abdominal ganglion, x about 100 diams. 



of it are two lobed appendages, thickly clothed with hairs 

 and scales, and not showing any very prominent difference 

 in the two sexes. In both they consist of a pair of olive- 

 shaped protuberances, but in the male, instead of ending 

 in a simply rounded, bristly extremity, they have articulated 

 to each a strong incurved claw, by which the female is 

 grasped during copulation, the whole organ forming a 

 clasper. In the female they are somewhat spatulate and 

 act as an ovipositor, being held together to form a sort of 

 channel along which the ova are passed on to the upper 



