82 ANIMAL ACTIVITIES. 
joint commonly called the body, and back of that the 
smaller joints of the abdomen. The end of the tail is 
double as shown in the figure. 
One projection is the insect's 
propeller, and the other its 
breathing-tube, which it is 
constantly using when at 
rest, opening or closing at 
will the tiny valve at its cx- 
tremity. The mosquito larva, 
then, breathes air directly 
and does not take it from the 
water like the young dragon- 
fly. Like its mother, the 
larva is bloodthirsty and 
always hungry. At the end 
of about two weeks, after 
PO es moulting several times, the 
dibles and maxille: “, eye. larva changes to a pupa, 
bending its head under its 
body as seen in the fouls and losing its mouth alto- 
gether, but retaining its power of active movement. 
The breathing-tube at the end of its body disappears 
and it now takes air by two tiny projections on its 
back. Finally, the pupa rises to the surface of the 
water and again moults, producing the adult mosquito, 
which uses its cast-off skin as a boat on which it floats 
until its wings are dry and it is ready to fly away. 
Should its frail boat capsize and wet its wings the 
mosquito would drown. It has been 
found that a little kerosene spread 
upon the water of stagnant pools 
will not only kill the egg-rafts as 
they float about but will also destroy 
P Fic. 75.—The Egg- 
the perfect insects as they emerge if aMieaullo, 
from their pupa-case boats. 
The imago now breathes, like other insects, by the 
spiracles along the sides of its body. It has but one 
