10 INSECTS AFFECTING HEALTH OF MAN OR ANIMALS. 
This fly is about the size of the common bluebottle blowflies and | 
of a metallic blue or green color. It may be readily distinguished bya 
three dark stripes running down the back between the wings. | A 
In tropical America an annoying parasite of man is the maggot of 
the Dermatobia fly. This maggot develops under the skin of a person a 
or animal, giving rise to a boil-like swelling, causing itching and pain. 
INSECTS WHICH CONVEY DISEASE BY BITES. 
Some of the most dangerous diseases of the Tropics are conveyed 
by the bites of blood-sucking insects. The diseases of this kind 
most to be guarded against in the Western Hemisphere are typhus 
Fig. 8.—A malaria mosquito, Anopheles quadrimaculatus: Male at left and female at right. Greatly 
enlarged. (Howard.) 
fever, carried by lice; malaria, yellow fever, and dengue or break- 
bone fever, carried by mosquitoes; and bubonic plague, carried by 
fleas from rats to man, and from man to man. 
Mosquitoes can nedlep only where there is water. The female ~ 
lee eges and oe these eggs hatch little worm-like larve called — 
‘““wrigelers”’ o r ‘ wiggle- tails” which live in the water. These larvee, ‘ 
although living in water, breathe air which they obtain by rising — 
to the surface at frequent intervals and bringing the breathing tube — | 
at the hind end of the body in contact with the air. When full grown ~ 
they transform into pupe, or “tumblers.” These are very stout -~ 
and usually of dark color; they float at the surface, but when alarmed - 
rapidly go to the bottom. After an interval of 2 or 3 days the pupa 
splits open along the back and the full-sized mosquito issues from it. 
