THE STABLE FLY. 17 
During warm weather the blood is digested rapidly and the flies 
may feed again the same day. When the weather is cooler they 
usually require about a day for the digestion of the blood. After 
partaking of a meal the flies, during hot weather, ordinarily alight on 
the walls of buildings or on foliage of plants in shady situations. 
When the temperature is lower they remain in the sunlight, but in 
all cases they tend to 
avoid strong wind. 
Adults frequently 
follow for considerable 
distances teams trav- 
ersing roads and, when 
engorged, settle on 
near-by objects. Other 
teams which pass along 
the same highways are 
thus frequently at- 
tacked by flies which 
have completed the di- 
gestion of their previ- 
ous meal, and this has 
given rise to the idea 
that the flies are breed- 
ing in weeds, grass, 
and hedges along the 
highways. This isalso 
a means by which the 
flies invade territory 
beyond that in which 
they develop. Adults 
have also been ob- 
served to travel many 
miles in the passenger 
coaches of railways. 
Few individuals are Fig. 6.—Legs of a steer attacked by the stable fly. (Author’s 
: 5 C illustration. ) 
carried in this way, but 
doubtless the spread of the species is aided and, what is more impor- 
tant, diseases might be spread in this way by infected flies. 
Feeding may take place a number of times. Experimentally, 
individual flies have been induced to engorge as many as 14 times. 
Flies have been observed to partake of water and to feed to some 
extent on succulent fruit. They commonly feed on the moisture on 
fresh manure and on rotting straw. Although man is occasionally 
bitten by these flies, horses and cattle seem to be preferred as hosts. 
540 
