242 THE HOUSE FLY—DISEASE CARRIER 
at farm yards, where they remain until the morning sun 
tempts them out. 
Both males and females suck blood. According to 
Osborn, while this fly inflicts a deep bite it does not 
gorge itself at a single animal, but may fly from one 
to another in securing a meal. From this fact he thinks 
the idea that this fly is apt to be a transmitter of glan¬ 
ders from diseased to healthy horses, and anthrax 
among cattle, receives important support. The punc¬ 
ture under ordinary circumstances does not seem to be 
poisonous to men, and aside from the pain given it is 
less dangerous than a mosquito bite. Newstead no¬ 
ticed a female drive its proboscis into the thorax of a 
dead companion and apparently suck up the juices of 
its body. The same writer permitted one to suck blood 
from his hand and observed it carefully during the 
process. The insect sat high on its legs, the whole of 
the proboscis was straightened and held vertically, and 
the lower third was driven into the flesh. During the 
process, which lasted fifteen minutes, the proboscis was 
constantly but somewhat slowly moved up and down, 
and also with an occasional semi-rotary movement, like 
the action of a quarryman’s hand drill. There was no 
subsequent irritation or soreness of any kind. The 
fly died twelve hours after feeding. During other ob¬ 
servations Newstead found that the flies lived for sev¬ 
eral days in captivity, and that the females died either 
immediately or shortly after laying their eggs. 
The biting house fly has almost as wide a geographic 
distribution as the true house fly. It was probably orig- 
