breathing, hang at a 45angle below the surface of the water. The adult mosquitoes rest
and feed with their bodies parallel to the surface (see figure 1-10). Some species such
as Aedes aegvpti bite during daylight hours and rarely come to Iight traps. Others bite
any time of day or night, depending on the species.
Figure 1-10. Typical resting positions of the Aedes and Culex mosquitoes in their larval
and adult stages.
(3) Culex mosquitoes breed in fresh or stagnant water around buildings as
well as in swamps, ditches, street gutters, cesspools, and almost 4 any other place that
holds water. The larvae hang at a 45 angle in the water; and the adults rest and feed
parallel to the surface, Iike the Aedes (see figure 1-10). Culex mosquitoes, depending
upon the species, may bite at any time of the day or night.
1-6.
LICE
Lice are in the order Anoplura. The most important member of this group is the
human body louse, which many people feel has had a more profound effect on our
history than any other insect. Lice thrive during hard times, when sanitary conditions
are poorest, and human populations are homeless and dislocated. For this reason
these insects have always been associated with wars. Entire wars have been lost
because of casualties due to louse-borne epidemic typhus. Three species of Iice are of
medical importance to humans: the body louse, the head louse, and the crab louse.
The body louse and head louse have overlapping structural characteristics that make
them difficult to identify. However, they can be distinguished based on their habits and
where you find them. The scientific names of these two species have a third name, the
subspecies, because of their extremely close relationship. All Iice have gradual
metamorphosis. Developmental stages include the egg, three nymphal stages, and the
adult (see figure 1-11).
MD0170
1-10