THE LIVING WORLD. 
253 
is the need for their services, and that equally great, at times, is the need for 
checking their undue multiplication. 
The mosquito is one of the best known species of gnats. Disagreeable as 
they are to one whose attention is absorbed by his own personal discomfort, they 
are among the most useful laborers in the field of animal economy. As one 
travels southward, the need for their services grows more pressing, and their 
presence and, as it seems to the ignorant, pernicious activity becomes more and 
more noticeable. In cities their number diminishes with improvements in drain¬ 
age, but experience would seem to 
suggest that their absence is bought 
at the cost of increase in frequency 
and fatality of several forms of 
disease; the disagreeable and the 
helpful, as well as the pleasant and 
the dangerous, are not always recog¬ 
nized. Mosquito-bars have doubtless 
become too well known to excite sur¬ 
prise in America, but the reader may 
not be aware that at no greater dis¬ 
tance than that of the Louisiana 
plantations, persons find it necessary 
to surround their rooms with a mos¬ 
quito bar that they may attend to 
the cares of household life. It is 
probably better known that in Min¬ 
nesota, and in forest tracks north as 
well as south, the lumbermen have 
at times to protect their heads and 
hands. In Africa the mosquito has 
been a more dangerous enemy than 
the savage tribes, dense jungles and 
dangerous streams with which Liv¬ 
ingston and Stanley had to contend. 
The eggs of the mosquito are laid 
in the water and float in little skil¬ 
fully constructed rafts upon its sur¬ 
face. Within a few days the larvae 
are hatched, and appear in the form 
of what children call wriggles. Dur¬ 
ing the pupal stage the mosquito 
changes its skin two or three times, 
and exchanges its breathing tube 
at the hips for two others, which proceed from the thorax. In tune 
pupa exuviates, and the young mosquito begins his career of labor attended by 
song far surpassing in its constancy the music-crowned labors of the wine-press, 
and calculated to render a real service to mankind, instead of betraying him by 
delights which inebriate but do not cheer. 
The larger sized species are frequently called gallinippers. The well-known 
daddy-long-legs belongs to this family, and the thinness of his dispropor- 
COMMON GNAT, {Culex pipiens), AND ITS METAMORPHOSES 
MAGNIFIED. EARV^E OPENING THEIR RESPIRATORY 
DOORS ON THE SURFACE OF THE WATER- NYMPHS AND 
PERFECT INSECTS. 
