Sheep Scab . 
83 
fibre, sometimes performing active movement with its legs, of 
which the mature parasite has four pairs. It is more distinctly 
seen with a magnifying lens ; or if some of the moist material 
from the border of a scab, mixed with a little glycerine and a 
[Photo, by P. W. Garnet, M.R.C.V.S. 
Fig. 7— Colony of Acari causing Sheep Scab. 
1. Ova. 2. Hexapod larva. 3. Nymph. 4. Pubescent females. 
5. Oviparous females. 6. Male. 
solution of soda, is placed under the microscope, mature acari, 
six-legged larvae, and eggs may usually be observed. It does 
not burrow, but lives and breeds on the surface, stabbing and 
G 2 
