8 Farmers’ Bulletin 1150. 
Sheep should be handled carefully, not roughly. Dip the bucks, 
ewes, and lambs separately. The sheep should be fed and watered 
from 3 to 6 hours before dipping, in order that. they may not be 
hungry or thirsty and yet not gorged with food. In hot weather 
they should be cooled off before dipping, and when the nights are 
cold they should be dipped in time to dry off before night. Ten days 
should elapse after shearing before dipping, in order that cuts may 
heal, especially when arsenical dips are used. Because of their ex- 
tremely poisonous nature it is usually inadvisable to use arsenical 
dips in treating sheep. j 
Prevention:—To prevent infestation with lice it is essential that 
contact with lousy animals be prevented and that animals free from 
lice be kept out of sheds, pens, inclosures, or pastures where lousy 
stock has been present within three weeks. After the first dipping, 
sheep should be put on clean pastures or held in clean inclosures to 
allow time for any eggs to hatch and the lice to die, or else the sheds 
and lots should be thoroughly cleaned out and disinfected before 
using them. For this sort of disinfection the coal-tar dips in double 
the strength used for dipping are satisfactory. 
THE SHEEP TICK.’ 
Location.—The sheep tick occurs in the wool and on the skin. 
Appearance.—The sheep tick is not really a tick, but is a kind of 
wingless fly (fig. 4). It has 6 legs, whereas the full-grown true 
ticks have 8 legs. The mouth parts are very similar to those 
of other flies. These insects are reddish or gray-brown in color, 
and are about a quarter of an inch long on an average, and may 
therefore be easily distinguished from the lice. ‘They are distinctly 
divided into head, thorax, and abdomen, which distinguishes them 
from the true ticks, which are occasionally found on sheep, as these 
true ticks have the thorax and abdomen fused. with the head not con- 
spicuously distinct. 
Life history.—The egg of the sheep tick is not laid as such, but is 
retained in the body of the female until it develops into a ie or 
pupa, which occurs in about seven days. The pupa is then de- 
posited by the tick and is attached to the wool of the sheep by a 
gluelike substance. When deposited it is covered with a soft, white 
membrane, which becomes brown and hard in about 12 hours. The 
pupe of the sheep tick are commonly called eggs. The young ticks 
emerge from the pupal stage in 19 to 24 days, the shorter time being 
in warm weather and the longer in cold weather. The tick is almost 
full-grown when it leaves the pupal case and it becomes mature in 
3 to 4 days. After copulation the female may deposit its first pupa 
in 8 to 10 days. 
2 Melophagus ovinus. For additional information see Farmers’ Bulletin 798 on “ The 
Sheep Tick.” 
