1915] Behavior of Anopheles 267 
This often means collision with unfavorable conditions, and the 
animal moves away, a negative response. If it copes repeatedly 
with such new conditions, it must become attuned to these 
conditions. If it cannot do so, it must give in to that form or 
association of forms that can become attuned. Successful 
attunement results in greater hardiness and ability to cope well 
with other new conditions. 
The gradual domestication of A. albimanus is the result of 
just such collision. The condition today is not the result of 
some sudden change, but represents gradual attunement. And 
probably the fact that the breeding at the swamp, which at 
first was largely albimanus s. s., later changing almost entirely 
to tarstmaculata, which presented conditions of extreme salinity 
and a difference in specific gravity, 1s another demonstration 
of just such collisions. There probably exists among the total 
of any species groups of individuals having one or more strains 
in them which permit them to endure conditions of greater 
stress. And so we may readily suppose that the transition 
from true albimanus to the racial variety tarsimaculata is the 
result of just such existant strains. 
(Specific) 
Regarding flight, two definite facts appear; (1), there is 
a marked flight during dusk and dawn, and (2), this movement 
stops with almost mechanical precision when there is too much 
or too little light. The evening flight was always low and 
deliberate. That of the morning was characterized by haste 
and took place higher in the air. The factor which determines 
the height at which the flight occurs is probably humidity. 
The duration of the flight depends upon the duration of the 
zone of light of that degree of intensity to which the mosquitos 
are accustomed to. 
Several laboratory experiments were made to determine the 
reactions of these mosquitos to light. A large number of A. 
tarsimaculata were confined in a large glass jar which was 
covered with several thicknesses of black paper. The top was 
covered with a board in which was drilled a one-half inch hole. 
Upon this cover was placed a lamp chimney with the top of 
it covered with gauze. 
