AUTUMN NUMBER 19 
(1901), in his Monograph of the Culicidae of the World, listed 
about six hundred species, over sixty of which are recorded from 
the United States. 
Naturally the first question that arises is, ““Where do all these 
pests come from?” “Where do they breed?” It is now known 
that, with a few possible exceptions that do not occur here, all 
mosquitoes are aquatic in their younger stages. They live under 
the surface of the water but are true air-breathers without gills 
and must come to the surface for air. The air is taken in through 
the trachael tube which ends in the prolongation of the eighth 
abdominal segment, called the anal or respiratory tube. This 
tube is pushed through the surface film and a supply of air drawn 
in. Later, in the pupal stage, they breathe through two trumpet 
like tubes arising from the top of the thorax. The food of these 
larvae consists of bacteria, slimes, and decaying animal and 
vegetable matter, while a few are carnivorous. Different species 
breed in different kinds of water. Some will breed only in salt 
water, others in clean fresh water, while still others prefer pol- 
luted sewerage. In studying the mosquito question for extermi- 
nation, it is important to know where and what kind of breeding 
places we have to contend with. 
The following species have been taken, but there may be others 
that occur rarely: 
“Culex quinquefasciatus Say. 
Anopheles crucians Wied. 
Anopheles quadrimaculatus Say. 
Stegomyia calopus Meig. 
Psorophora ciliata Fab. 
Psorophora floridense D. & K. 
Megarhinus sp.? 
Following is a brief description of these species: 
CULEX QUINQUEFASCIATUS 
Eggs.—This is the commonest species. The eggs are somewhat conical 
in shape and are laid on the surface of the water with the large end down. 
They are placed side by side and stuck together, forming a boat shaped 
raft (Fig. 1) of six to thirteen rows with forty eggs in a row, each raft 
containing from one hundred to four hundred eggs, with an average of one 
hundred and seventy-eight and four-tenths (Davis 1906). They are white 
when freshly laid, but soon turn grayish brown to black as seen from above, 
and silvery grayish below, due to a film of air which protects the eggs 
from the water. They usually hatch in from sixteen to twenty-four hours 
but they have remained unhatched in the laboratory for ten to twelve days. 
A few hours desiccation kills them. (Mitchell 1907.) 
The eggs are usually laid at night or early morning, but I have observed 
