14 INSECTS AFFECTING HEALTH OF MAN OR ANIMALS. 
be repeated that refuse containers of all kinds, barrels for contaming — 
rain water, the drinking vessels of poultry, as well as watering — 
troughs, cisterns, etc., are favorite resorts of the yellow-fever and — 
house mosquitoes. In fact, larvee frequently occur in such small 
collections of water when none are to be found in the larger and — 
more obvious bodies. i 
Running streams, if not too rapid, especially if the banks are over- 
hung by grasses or other vegetation to afford protection, or if there are 
hollows and indentations along the banks beyond reach of the current; 
swamps or bogs in the 
~ small meadows which 
| Pi are often found along 
\ ey the course of mountain 
Chie fale a y streams; hollows and 
Wwe | water holes in arroyos or 
gulhes, otherwise dry; 
and pot holes in the 
rocks of stream _ beds, 
must all be included 
among the breeding 
. places of mosquitoes. 
See Methods of mosquito © 
7 
“dif Fi 
Vi 3 Te Rarer 
TTT AINE BO SLT 
yy 
a » 
“64 
A control may be either — 
\ permanent or temporary. — 
= Permanent control is ef- — 
, NS fected by means of drain- | 
y \ ; age, which renders the — 
/ \ Ng area involved perma-— 
: ‘ nently incapable of re-— 
taining water a sufficient — 
time for the growth and ~ 
: transformation of the 
ya any young mosquitoes. Tem- 
| . porary control aims at 
Fie. 13.—The yellow-fever mosquito (Aedes calopus): Adult era dication of mos quito 
female. Muchenlarged. (Howard.) 2 i ; 
breeding for the time — 
only, and is usually effected by means of oiling of water surfaces, 
sometimes with the addition of the cutting of vegetation, grass, or 
bushes, which afford shelter for the adult mosquitoes during their 
passage from the breeding place to human habitations. Where the 
vegetation is dense and the cover afforded mosquitoes is good, the 
growth should be cleared for a radius of not less than 1,000 feet. 
However, it is difficult if not impossible to specify exactly an effec- 
tive distance, as this will vary with the conditions and the species of 
mosquitoes involved. A narrower radius than 1,000 feet may be 
