266 Annals Entomological Society of America [Vol. VIII, 
up. Then came a strange performance. From the anal 
opening squirted out small droplets of clear liquid, shghtly 
alkaline, and which the writer believes may be a part of the 
salivary fluids which entered the wound. These droplets 
soon assume a light reddish tinge which gradually increases 
in depth until blood-red. By allowing these droplets to fall 
upon a cover glass and examining these microscopically, it was 
learned that they actually were human blood. Darling (1912, 
p-14), refers to a similar reflex. In 1902, Schuffner noted 
the same performance, and probably further investigation will 
show that the salivary fluid which enters the blood is not for 
the purpose of preventing coagulation, but rather to flush out 
and prepare the alimentary tract for the blood meal. Labora- 
tory experiments made by the writer indicate that after an 
Anopheles has gorged itself with blood, it does not feed ae 
until the pellet of waste had been expelled. 
The insect gorges itself with blood until often it increases 
the weight by two times. Darling (1912, p. 14), gives the 
weights of several albimanus, his data being: 
Bred in laboratory, 24 hours old, midgut empty..................... 0.0008 gms. 
Bred. in laboratory, moderate blood feeding...:............2..0..... 0.0016 gms. 
Caught in labor cars, some blood in midgut, half-developed ova...... 0.0019 gms. 
Caught in labor cars, much blood and early development of ova...... 0.0035 gms. 
Caught in laber barracks, blood in midgut, no development of ova... 0.0018 gms. 
Caught in labor barracks, blood in midgut, no development of ova... 0.0021 gms. 
4. Regarding the Behavior of Anopheles. 
(General) 
Behavior is adaptation to the environment. The focus of the 
environment and the behavior of the organism is the physio- 
logical state of the animal—a dynamic condition. External 
stimulh, if they are to cause change, must enter and alter the 
existant physiological state. If the stimulus does not produce 
movement, it may produce a new change in the physiological 
state. But a given stimulus which produced a certain change, 
may not produce the same ecleala always. For example, 
hunger may modify a response. 
High humidity, winds, salinity of water, etc., may alter 
the environment and by so doing, create a condition of stress. 
The result of all change is relative unstable equilibrium, and a 
tendency exists to relieve this stress and approach equilibrium. 
