286 MOSQUITOES OF NORTH AMERICA 
was breeding abundantly. Discarded bottles and tins about houses are favorite 
breeding-places. Dutton, at Bathurst in Gambia, found many boats lying on the 
beach containing collections of water, in some cases one or two feet deep. This 
water almost universally contained mosquito larve of five species, the most 
abundant being Aédes calopus. 
Occasionally the larvee occur in water in holes of trees, but only when these are 
in close proximity to human habitations. In a small grove of fruit trees in the 
town of Tehuantepec, Mexico, Knab found the larve in water at the base of the 
branch of a mango tree; there were numerous larve in the water-filled holes of 
two other trees in the same grove. In the village of San Antonio, near Sonsonate, 
Salvador, Knab again found larve of calopus in a hole in a large mango tree. 
Jennings found larve of calopus in the hole of a tree, near buildings, at Ancon 
in the Panama Canal Zone. 
Goeldi, at Para, found the larve in water-bearing bromeliads, presumably 
near houses, and in the still folded leaves of banana plants. Peryassti also 
records the larve of calopus from bromeliads at Rio de Janeiro. H. W. B. Moore 
of the British Guiana Museum has sent us specimens of calopus bred from 
bromeliads at Georgetown. He has since found the larve again in similar situa- 
tions and writes us in this connection: “The Bromelias from which I bred 
calopus were not very far from dwellings. On August Monday (Bank Holiday) 
I took a trip into a sparsely populated district where I have not yet collected, and 
got more calopus larve in Bromelias. Is it not likely that Bromelias and other 
such water-holding plants were the great natural breeding-places of calopus 
before it took seriously to breeding in man’s receptacles? It is evident that it 
is still one of their natural breeding-places, but they do not succeed as well there 
as some other species.” We are inclined to consider the conditions indicated by 
Mr. Moore as exceptional and due to the excessively moist climate of British 
Guiana. Our belief that calopus originally bred in tree-holes is supported by 
the fact that related species with similar habits breed mostly in holes in trees; 
moreover it is very rarely that species of the genus A édes resort to bromeliads. 
The Brazilian observers have found the larve of calopus in brackish water on 
a wharf on the Ilha das Cobras in the bay of Rio de Janeiro, the water showing 
a salinity of 35 per cent of sea-water. 
BEHAVIOR OF LARV. 
The larvee of calopus when suspended from the surface film, to take in air, 
hang almost perpendicularly. They are very easily alarmed and then go quickly 
to the bottom where they remain a considerable time. They can live under 
water, without rising to the surface, for a long time and this is also true of many 
other tree-hole inhabiting species of Aédes. When water is poured from a 
receptacle inhabited by calopus larve these quickly seek the bottom and their 
presence may not even be suspected although the vessels be in constant use. 
They cling so closely to the bottom that unless the jars are tipped up so as to 
empty them completely, which is not usually done, nearly all the larves remain 
in the jars. 
