The Two-winged Flies 
3 °5 
some have aquatic immature stages and some terrestrial; while the larvae 
and pupae of all the members of the remaining three live in plants or in the 
ground, none being aquatic. 
Best known of the aquatic families, and indeed of the whole suborder, 
is the mosquito family, the 
Culicidae. While the different 
kinds of mosquitoes are much 
alike, so much so indeed that 
most of us are quite content if 
we can determine an insect to be 
a mosquito without carrying the 
identification farther, there are 
known in the world at least 300 
different mosquito species, rep¬ 
resenting two dozen distinct 
genera. In North America 
nearly 60 species are already 
known, representing 10 genera, 
and new ones are being found 
constantly. In the family Culi¬ 
cidae are included two distinct 
general types of mosquito, one 
with mouth-parts forming a long, 
slender, sucking proboscis, pro¬ 
vided with sharp, needle-like 
stylets for piercing (Fig. 411), the 
other with the mouth-parts short 
and better adapted for lapping 
or sucking up freely exposed 
liquids. The latter type of 
mouth is possessed by but two 
genera, all the others being 
piercers and blood suckers (in 
the female sex). Of these pierc¬ 
ing genera three are of especial 
importance and interest to us 
because of their abundance and 
their definitely determined relation to the development, incubation, and dis¬ 
semination of certain serious diseases of man. These three genera are Culex, 
Stegomyia, and Anopheles. To Culex belong the great majority of familiar 
mosquitoes which pursue and harass us with their songs and bites; to Stego¬ 
myia (and Culex) belong the mosquitoes held responsible for the dissemination 
Fig. 413.—The life-history of a mosquito, 
Culex sp A small raft of eggs is shown on 
the surface of the water, several larvEe 
(“wrigglers”)? long an d slender, and one 
pupa (“tumbler”), large-headed, are shown 
in the water, and an adult in the air above. 
(From life; much enlarged.) 
