EGGS OF SABETHINI 145 
species against destruction in such case, exists in the fact, already mentioned, 
that not all the eggs hatch, a part of them lying over until again submerged by 
subsequent rains. 
Certain species of Aédes and Stegoconops are partial to the water in hollow 
trees and these are almost continuous breeders during favorable conditions and, 
while they are dependent to a certain extent upon rains, they show no well- 
marked broods. These species deposit their eggs near the water, usually close 
to the moist margin above it, and the eggs hatch when the water rises to them. 
The water in such holes in trees is usually well protected against desiccation and 
every slight rain contributes to it; as a comparatively slight rise of water will 
reach the eggs, these can hatch at frequent intervals. The yellow-fever mosquito 
(Aédes calopus), although so closely associated with man, is in its habits es- 
sentially a tree-hole species. The eggs are deposited in the same manner, only, 
through the fact that they are deposited in water receptacles which are being 
constantly refilled by man, the chances for the hatching of the eggs are greatly 
increased and, to a large extent, made independent of weather conditions. 
Little is known of the eggs or egg-laying habits of the tribe of Sabethini. We 
have already mentioned that Joblotia digitatus lays its eggs in a raft. Other 
species of Joblotia lay their eggs singly upon the water. 
Smith found that with the pitcher-plant mosquito (Wyeomyia smithii) the 
favorite place for the disposal of eggs is the younger leaves which had not yet 
filled with water. The eggs were found in abundance upon the inner surface of 
such leaves ; they were also found in lesser numbers, floating upon the water in 
the older leaves, and the oldest leaves had the fewest eggs. Busck, in Trinidad 
and Panama, found certain species of Wyeomyia breeding in the flower-spathes 
of Heliconia. The eggs were found deposited in the uppermost, still unex- 
panded, spathes of the series, which as yet contained no water. 
