The Ox Warble or Bot Fly. 
67 
terror experienced may be associated with the buzzing of the 
breeze or other flies which bite. 
Prevention . — When the warble is noticeable in the skin, the 
injury to the hide is done. Our attention should therefore be 
specially directed to the adoption of measures for preventing the 
fly from depositing eggs. As there is reason for believing that 
the warble fly lays its eggs only in bright warm sunshine, and 
avoids shade and water, the shade of trees, sheds, &c., should 
be accessible to the cattle, and, where practicable, water to stand 
in during the hottest parts of the day. The application of certain 
dressings to the skin from the beginning of May to the middle 
of September is of great service in deterring the fly from 
depositing eggs. Of such dressings there are many available. 
Few flies will alight on the skin which has lately been treated 
with paraffin, or paraffin and grease ; but the effect is not 
enduring, and repeated applications must be made, while there 
is a degree of danger connected with extensive use of this 
agent. Stockholm tar is probably the most enduring, and 
the application is necessary only three or four times during 
the summer. Monthly dressings with a mixture of ha eiJ pint 
of oil of tar, a pound of flowers of sulphur, and a ga urn of 
train oil, have been successfully employed for many ^ears, 
and probably nothing is safer and better. 
It has been the common practice to dress only the back 
and upper parts of the body, but in view of the known habits 
of Hypoderma lineata, and doubt about those of Hypoderma 
bovis, it is well to include the legs. When the warble is 
noticed in the skin (from January or February till May), 
the maggots should, when practicable, be squeezed out 
and destroyed by squashing or burning. If a little paraffin, 
pickling brine, or mercury ointment be applied to the 
warble a few hours before, the maggots are squeezed out more 
easily. When very numerous, the parts may be smeared with 
grease or mercury ointment, but with the latter great care is 
required, and a small quantity only must be used, and only 
a small part of the skin dressed at one time. It is stated 
by more than one authority that, naturally, the maggot leaves 
the skin only in the early hours of the morning, and it is 
advised in severe infestations of animals to place them in the 
house at night, and sweep up and destroy all maggots on the 
floors. 
As it is probable that winter residence in the skin or 
tissues of cattle is absolutely essential, if all the maggots in 
the cattle of a district were destroyed, infestation in the coming 
season would to a large extent be averted. Indeed this special 
condition in the life-history of the bot fly suggests that con- 
certed action might annihilate the species in this country. 
