284 MOSQUITOES OF NORTH AMERICA 
upon the human species is undoubtedly of ancient development. The preference 
for human blood is well demonstrated, and, as has been pointed out, the work 
done by several investigators seems to prove that calopus does not oviposit until 
after having had a meal of human blood. Although Goeldi has shown oviposition 
after a meal of guinea-pig blood, he considers human blood more efficacious 
in bringing about ovulation. 
We have already demonstrated that calopus is essentially a town mosquito. 
The larvee are found practically exclusively in artificial receptacles about human 
habitations. It may be said that the larve of calopus are never found in swamps, 
in pools or in temporary puddles, even when these are in close proximity to 
houses. Durham, who studied the species at Para, makes the following state- 
ment concerning the breeding-places. “Casual water in vessels, etc., in and 
about houses such as buckets, tins, washtubs, rain gutters, ant-guards (per- 
forated troughs to protect plants in gardens, and sugar, ete. in houses), larger 
and deeper collections of water as casks or hogsheads full of rain water. Also 
in bilge water of barges, lighters, and 8. S. Viking (Amazon Telegraph Co’s 
ship, many years on the river). Not found in sewage collections as cesspools, 
stable runnings, etc., although found in neighbourhood in cleaner waters. Also 
not found in natural puddles in forest or streets, etc.” We are well aware that 
there are a number of records of calopus larve occurring in street puddles and 
in swamps, but it would seem that in these cases the larve were not bred and 
most probably they were those of some other species of Aédes, many of which 
greatly resemble calopus in general appearance. 
In the tropics the large earthen jars in which drinking water is kept are the 
most frequent and unfailing habitat of the larve. Rain-water barrels are abun- 
dant breeding-places. In New Orleans and other southern cities, like Galveston 
and Mobile, rain-water tanks, so abundant behind the houses, are probably the 
source of the most abundant supplies of these mosquitoes. Reed and Carroll 
state that in their search for the larve of this insect in Cuba they found them 
in the following places: “ (1) In rain-water barrels; (2) in sagging gutters 
containing rain water; (3) in tin cans that had been used for removing excreta 
and which still contained a small amount of fecal matter; (4) in cesspools; (5) 
in tin cans placed about table legs to prevent the inroads of red ants; (6) in the 
collection of water at the base of the leaves of the agave americana; (7) in one 
end of a horse trough that was in daily use.” 
In New Orleans, in the epidemic of 1905, water-closet tanks were found to be 
abundant breeding-places, and Surgeon White suggested that an ordinance be 
made and enforced to cover these tanks with wire gauze. They were also found 
breeding in the accumulation of water in the drain traps of stationary wash- 
stands. Roof gutters, in New Orleans, were especially noticed on a number 
of occasions, where they sagged, to contain large numbers of calopus larve. 
Another interesting place where they were found breeding was in the urns in the 
cemeteries. In the autumn of 1905, at New Orleans, Surgeon Richardson, of 
the Public Health and Marine-Hospital Service, told one of the writers 
(Howard) that at Laredo, Texas, in the outbreak of 1903, calopus was found 
