STRUCTURE 



425 



General Structure. — Mosquitoes are members of the great 

 insect order Diptera, to which so many human pests belong. 

 Their nearest relatives, outside the mosquito family itself, are 

 the midges (Chironomidae), craneflies (Tipulidae), sandflies 

 (Phlebotomus), and blackflies or buffalo gnats (Simuliidae) . The 

 members of the mosquito family, Culicidae, can be distinguished 

 from other Diptera which look more or less hke them by the 

 characteristic and quite conspicuous fringe of scales on the hind 



df.res.- 



Fig. 189. Digestive tract of a 



mosquito; d. f. res., dorsal food 



reservoirs; malp. t., malpighian 



tubules; ph., pharynx; prov., pro- 



FiG. 188. Diagram of adult female mos- ventriculus; rect., rectum; sal. d., 



quito {Aedes sollicitans); abd., abdomen; salivary duct; sal. gl., salivary 



ant., antenna; c., eye; halt., haltere; palp., gland; st., stomach; v. f. res., ven- 



palpus; prob., proboscis; th., thorax. tral food reservoir. 



margin of the wings. Most of the Culicidae have a long promi- 

 nent proboscis containing needle-like organs for piercing and 

 sucking, but in two subfamilies, including the midges of the 

 genus Dixa, and the so-called phantom midges, Corethra (Fig. 

 192), the adults of which resemble true mosquitoes and are often 

 mistaken for them, there is no long proboscis. 



The general appearance of adult mosquitoes is so well known 



