[...]
Of
all the blood sucking insect pests which played mankind the
mosquitoes among the most pernicious.
Mosquitoes are divided into two great tribes.
The anopheles some of which transmit malaria assume this position in biting.
And the cure the things which may spread yellow fever dengue and filler I.
[...]
Is this right in this position.
The mosquito body is divided into three parts.
The head.
Thorax.
And abdomen.
The thorax bears three pairs of legs and a single pair of wings.
The head bears the eyes the feelers around teni the paltry and the beat.
The abdomen bears no special structures except the reproductive organs.
In the female the antennae are fringed with short hair rising
from the edge of each segment.
While in the mail.
The antennae are conspicuously tufted with large worlds of hair.
The prominent antennae are the chief distinguishing features of the mail.
A mosquito bites primarily to obtain food.
As the female settles down to a blood meal her beak
appears to bend at the middle.
Actually the beak consists of a jointed protective sheath that bends.
While a thin lancet enclosed within the sheath pierces the skin.
A cross section of the beak shows that this lancet consists of
six separate stylus.
Which in close between them two tubes one for saliva and one for blood.
A small amount of the insect saliva is injected into the wound to prevent
clotting of the blood which is then sucked up as food.
The abdomen swells perceptibly as the blood meal progresses.
A male mosquito cannot bite or suck blood.
A newly emerged male may try blood suction without success.
The beak of the male is not constructed to pierce human or animal skin.
Male mosquitoes feed exclusively on vegetable juices.
The nectar of flowers.
The juice of fruits.
The female also feeds on vegetable juices but blood forms
the major part of her diet.
Some mosquitoes lay eggs on the surface of water.
Some near the water.
Some mosquitoes like shaded water.
Others some lit.
Some require fresh water.
Others prefer salt.
But all mosquitoes require water of some kind.
Flood water mosquitoes lay their eggs singly in mud near water or in other areas
which later may be covered with water.
The eggs of flood water mosquitoes can remain dormant sometimes for years until
the conditions of warmth and water are suitable for hatching.
Flood water mosquitoes living in regions having cold winters
overwinter in the egg stage.
A section of frozen mud taken from a swamp where flood water mosquitoes are known
to breed in summer when immersed in water at room temperature will cause mosquito
larvae to appear a few days later.
Most other mosquitoes overwinter in the adult stage.
Such hibernating adults can be found in hollow trees, in culverts,
under houses, porches or in cellars.
These mosquitoes lay eggs fitted with two floats on the surface of the water or
in large buoyant masses called egg boats.
Except when overwintering, mosquito eggs hatch into larvae soon after they are
laid, sometimes in less than a day.
The mosquito larvae after hatching is usually whitish or gray in color.
Floating at the surface of the water, it inhales air through its breathing tube.
It soon moans, shedding the original larval skin, emerging somewhat larger into
the second instar or period of larval development.
In the same way, the larva passes through the third
and into the fourth
and last instar.
The larva has no legs or other organs of locomotion and moves by a series
of jerks or wiggles.
In some species, the body of the larva is transparent
and the heart action may be observed.
As in all insects, the contraction waves begin posteriorly at
advanced anteriorly.
Watch closely this tail-to-head pulsation.
The head and thoracic segments of the larva are enlarged, sometimes twice as
broad as the abdominal segments.
The abdomen is divided into nine segments, the first seven of which resemble each
other closely and differ little in species.
On the ninth segment are the anal gills. On the eighth segment, tube
through which the larva breathes.
Most larvae hang head down with the breathing tubes at the surface of the water.
The anophilus larva, however, lies horizontally
when feeding at the water surface.
Examined closely, the mouth parts are seen to be in constant motion.
The anophilus larva, which can turn its head 180 degrees to facilitate feeding,
sets up currents at the water surface with its mouth brushes to bring within
range the floating particles on which it feeds.
When the larva has reached the fourth instar, appendage buds, which will later
grow into the legs and wings, can be seen on the ventral side of the thorax
through the semi-transparent cuticle.
In the second instar, these appendage
buds, while already differentiated, are not yet well enough developed to be
visible at this point of growth. Full grown,
the larva now begins the change through the pupil form. Telescoping its body
slightly, it commences to shed its cuticle, usually beginning at the head.
For a while, the insect may rest, its new pupil head
projecting from its larval body.
Finally, with a few convulsive jerks, the larval cuticle, complete with breathing
tube, is cast off, and the mosquito assumes a new
guise, that of a pupa.
In this stage, no food is taken, although the body remains in water. The pupa has
its head and thorax punched into one mass, with no obvious organs except two
black spots, which will later become eyes, and two horn-shaped appendages
at the top of the thorax, which serve as breathing tubes.
The abdomen terminates in two swimming paddles, which
propel the pupa through the water.
As the pupa grows older, the wing pads become recognizable. Holded up against the
wing pads are the cases of the long, jointed legs of the adult. The pupil stage
is short-lived, lasting usually only one to four days in warm weather. When the
adult is fully developed within the pupil case, the pupa is less active. It tends
to straighten out and takes on a shining, glittering appearance.
Suddenly, the skin bursts along the middle of the back.
The adult rises up almost vertically, literally oozing out of the pupil envelope.
The wings are first freed.
Finally, the long legs are carefully extended to support the
fully developed body.
In a few minutes, the drying process is complete. The insect
is now ready to fly.
With this final transformation, there has evolved the familiar adult mosquito.
The mosquito is an excellent example of an insect
undergoing complete metamorphosis.
The egg, the larva, the pupa, and the adult. Truly, the female of the species
is more deadly than the male.