Evening star. [volume] (Washington, D.C.) 1854-1972, 1910-07-17
Incubator MOSQUITOES
Continued from page s

might imagine that she would need some
sort of support; but she doesn't.
Nearly everybody has observed the way in
which a sewing needle, if perfectly dry, can
be made to float. 1t rests. as it we're, upon
film; which, however, is not really film in
the ordinary sense of the word, but a mole
cular arrangement depending upon certain
principles more interesting to the student OF
physics than to everyday folk. A drop of
water is covered by such film, and for that
reason assumes and holds, unless too vigor
ously disturbed, the shape of ball.
The insects called water striders,' which
skate about on still ponds, perform their
evolutions on this film much in the same
way as boys skate over the ice. Close in
spection of one of them will show a dark
spot about each foot, which in effect is
shadow, marking a depression in the film.
But, as everyone has noticed, water is &C
tually repealed by dryness, and the water
SO long as 1t does not get its feet wet.
1t is exactly the same way with the lady
mosquito. Standing on the water, she lays
her eggs, from one hundred and fifty to three
hundred in number ordinarily, the operation
requiring several hours. She may then be
| transferred to a little wire cage or some other
suitable receptacle if she is wanted for fur
ther use, the eggs being left in the bottle to
hatch at leisure. When the wriggers APP
pear, it is best to transfer them, with the
help of glass eye dropper, to small jar,
where they will have plenty of room to I'M
dergo their subsequent transformations.
Now, through study of this kind in the
laboratory many facts about mosquitoes have
been learned which were not previously
known. One is that females commonly lay
of ono hot of 1,,t
1t is necessary, however, that they shall
have drinks of blood between layings, to sup
ply the requisite albumen. Often they lay as
many as nine patches, and Anopheles, the
malaria carrier, produces seven or eight.
A Mosquitoes Biography
A TTACHED to the staff of the Smith
sonian Institution in Washington is a
young woman Miss Evelyn Mitchell, who
is one of the foremost living authorities on
mosquitoes. She has bred at least thirty
five different species of them, and has ex-
pended no small quantity of her own vital
fluid in furnishing them with meals. One
record she has of malaria mosquito, kept
in captivity nineteen days, which gives the
following details:
Fed blood, March 49,
Eggs laid 1902 in NUMBER, April 2.
Fed blood, April 7.
Eggs laid (34D, April 7.
Eggs laid 1868, April 10.
Fed blood, April 10.
Eggs laid (272), April 13.
Fed blood, April 10.
Eggs laid (257, April Is.
Fed blood, April l9.
Eggs laid Q34), April %.
Died, April %. No flowers
This makes total of fifteen hundred and
sixty nine eggs laid by one female Doubt
less it often happens that lady mosquito will
lay more than two thousand eggs during her
breeding season, if well supplied with blood
The specimen in this case was Anobheles
bunchpennis, one of the three species of Ano-
pheles known to carry malaria in the United
States.
If mosquitoes depended wholly upon hui
man beings for their supply of blood, they