336 The Diseases of Animals 
spring, forming the lumps commonly known as “war- 
bles.” When fully developed, the larve, or “grubs,” 
work their way out through small openings in the skin, 
drop to the ground, into which they burrow and pupate, 
finally emerging as adult flies. 
These bot- or gad-flies of the ox cause much loss 
to the cattle industry, not only on account of the serious 
discomfort visited upon cattle by the adult fly in de- 
positing her eggs, but also by the damage to hides due 
to the presence of the openings over the ‘“warbles.” 
“Grubby” hides are usually docked one-third in the 
market. 
All adult bot-flies observed about cattle should be 
killed, and, from January on, every “warble” should 
be treated by applying turpentine to the small pore 
or opening directly over the lump. This will kill 
most of the warbles; the few that remain should be 
squeezed out and destroyed, each one so treated pre- 
venting the development of a fly. If this practice were 
generally and carefully followed, the fiy could be exter- 
minated. The adult flies do not travel far, so that a per- 
son, by this means, can largely rid his own eattle of this 
pest. 
SHEEP BOT-FLY, “GRUB IN THE HEAD” 
There is a small brown fly (Gstrus ovis), about the 
size of the common house-fly, which in the summer and 
fall is seen in swarms abont flocks of sheep. It greatly 
annoys the animals hy depositing living larvee in the 
nostrils. To avoid these pestiferous flies, the sheep 
often stand with their noses close to the ground, 
