286 MOSQUITOES OF NORTH AMERICA 



was breeding abundantly. Discarded bottles and tins about houses are favorite 

 breeding-places. Button, at Bathurst in Gambia, found many boats lying on tlie 

 beach containing collections of water, in some cases one or two feet deep. This 

 water almost universally contained mosquito larvae of five species, the most 

 abundant being Aedes calopus. 



Occasionally the larvae 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 larvae in water at the base of the 

 branch of a mango tree ; there were numerous larvae 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 larva3 of calopus in a hole in a large mango tree. 

 Jennings found larvge of calopus in the hole of a tree, near buildings, at Ancon 

 in the Panama Canal Zone. 



Goeldi, at Para, found the larvae in water-bearing bromeliads, presumably 

 near houses, and in the still folded leaves of banana plants. Peryassii also 

 records the larvae 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 larvae 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 larvas 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 Aedes resort to bromeliads. 



The Brazilian observers have found the larvae of calopus in brackish water on 

 a wharf on the Ilha das Cobras in the bay of Eio de Janeiro, the water showing 

 a salinity of 35 per cent of sea-water. 



BEHAVIOR OP LARV^. 



The larvae 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 Aedes. When water is poured from a 

 receptacle inhabited by calopus larvae 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 larvae remain 

 in the jars. 



