P. communis ovis is the cause of sheep scab.
ll. Pedicel of the suckers not jointed; mandibles chelate.
m. No suckers on the legs of the females; parasitic on birds, including chickens. C. mutans is itch mite of chickens. Cnemidocoptes Fürst.
mm. Suckers at least on legs I and II; parasitic on mammals.
n. Legs very short; in the male the hind pairs equal in size; body usually short. Sarcoptes Latr.
S. scabiei is the itch mite of man ([fig. 56]).
nn. Legs more slender; in the male the third pair is much larger than the fourth; body more elongate.
o. Female with suckers on the fourth pair of legs. Species do not burrow in the skin, but produce a scab similar to sheep scab. They occur in the ox, horse, sheep and goat. Chorioptes Gerv.
C. symbiotes bovis of the ox has been recorded a few times on man.
oo. Female without suckers to the fourth legs.