10 Farmers’ Bulletin 1150. 
of coal-tar dip should also be used, but this can not be depended on 
to kill the pupe, though it is useful in killing the ticks that might 
escape a cleaning process. To disinfect stone or wire-fence corrals, 
brush or straw may be scattered over the surface of the ground and 
burned. Clean sheep must be kept away from contact with ticky 
sheep and care must be taken to see that goats or other animals do 
not convey ticks to the sheep, Even persons may occasionally carry 
ticks for a short time 
in their clothing, and 
this must be kept in 
mind at shearing time 
and whenever there is 
danger of infection 
from persons who 
travel from one flock 
of sheep to another. 
SHEEP-SCAB MITE.’ 
Location.—On the 
skin. 
Appearance.—These 
parasites are very 
small animals, com- 
monly called scab mites 
(fig. 5). The male is 
only 0.5 mm. (one-fifti- 
eth of an inch) long 
and the female 0.625 
mm. (one-fortieth of 
an inch), but they may 
be seen with the naked 
Fic. 5.—Sheep-scab mite (Psoroptes communis ovis). CY as small white eb- 
Female. Back view, greatly enlarged. (After Salmon jects, especially when 
and Stiles, 1898.) ; 
placed on a dark back- 
ground. It is easier to see them when they are warmed, by sun- 
light or otherwise, on such a background, as they may then be 
seen in motion. The full-grown mites have 4 pairs of legs and 
these legs have long hairs. In the female there is a so-called 
sucker on a jointed stalk on the tip of the first, second, and fourth 
pairs of legs, and in the male on the first, second, and third, the 
fourth pair in the male having a sucker Shrek is not on a joimed 
stalk. 
®* Psoroptes communis ovis. For additional information see Farmers’ Bulletin 7138 on 
“Sheep Scab.” 
