OBSERVATIONS 
ON 
WARBLE FLY oe OX BOT FLY, 
(Estrus bovis, Clark ; Hypoderma bovis, DeGeer. 
Ox Warble Fly. 
The following observations have been collected in order to place 
before those interested in the subject some amount of information in 
a form easy of access regarding the history of Ox Warble attack, and 
means found practicable and serviceable for its prevention in this 
country, at the present time, by our own agriculturists and cattle owners. 
Little has been written in connected form on this attack since the 
time of Bracy Clark’s well-known treatise. German writings, 
especially those of F. Brauer, give much scientific information, but 
they are not easily accessible ; and the following observations there¬ 
fore have been courteously intrusted to me for publication with the 
view of drawing attention to the subject, and also of showing how the 
matter stands in our country without being encumbered by confusion 
from differences of climate, breeds, and treatment involved in working 
on foreign observation. 
Warble attack is commonly known as consisting of swollen lumps 
—few or many—to be found chiefly during the months of April and 
May on the back or loins of the attacked animals, each swelling or 
warble containing a maggot or “ bot,” which lies with its black-tipped 
tail (often taken for its head) at a small opening in the swelling, and 
the other end (which contains the orifice which serves for a mouth) in 
a sore on which it is feeding in the under tissues of the hide. 
The great injury, however, which is caused year after year by this 
attack is not only from the perforations of the maggots lessening the 
