a handbook of the mosquitoes of north america - Systematic Catalog ...

CHARACTERISTICS 27
above the first pair of legs. The ducts from each gland unite
near their bases to form a single duct on each side; these lat-
eral ducts converge and pass forward into the head where they
unite at the anterior end of the pharynx to form a common
duct. The common duct leads to the drum-like membranous
pump situated at the base of the hypopharynx. The salivary
fluid is forced into the wound by the pump along a gutter ex-
tending from the base to the tip of the hypopharynx (Fig.
4). The glands are simple in structure, each consisting of a
lumen lined with a single layer of secretory cells. The finer
structures of each gland seem to differ somewhat. These glands
are of great importance as the sporozoites of the malarial organ-
ism congregate within their cells and are passed out with the sal-
ivary secretion. What the exact function of the saliva may be is
not known though evidence indicates that it does not prevent
coagulation of the blood nor aid the steady flow of the blood
into the mosquito’s alimentary canal, as is generally stated.
The reproductive organs of the female consist of a pair of
lobulate organs located in the abdomen. Each opens by a
duct into a common oviduct which extends posteriorly to its
external opening in the eighth segment. Into the common
oviduct open the seminal receptacles and a cement gland. The
male genital organs consist of a pair of testes located in the
eighth segment from each of which leads a vas deferens. These
unite just before opening to the exterior into a common ejacu-
latory duct. The latter terminates in a short penis which is
guarded by an elaborate arrangement of claspers and various
chitinous structures whch are termed the Iz.ypopygium. The
structure of the male hypopygium is very important from the
standpoint of classification and a full account of it has already
been given.
The respiratory, circulatory and nervous systems correspond
closely to those generally obtaining in all insects and it does
not seem worth while to discuss them in a brief hand-book.2
2 Consult Comstock, An Introduction to Entomology. (1924) ; or
Imms, A General Textbook of Entomology (1924).