— ~~ eee 
270 INSECTS AFFECTING DOMESTIC ANIMALS. 
The varieties so retained are hominis, infesting man; scabiei crustose 
Furst., for the so-called “‘ Norway itch;” equi, for the form infesting the 
horse; ovis, on the sheep; capre, on the goat; cameli, on the camel; auch- 
enie, on the llama; swis, on the hog; cuniculi, for the rabbit and hare; 
Jfuronis, on the ferret; canis, on the 
dog; lupi, on the wolf; vulpis, on the 
fox; leonis, on the lion, and wombati, 
on the wombat. 
All stages of the parasite occur 
on the host upon which it is abso- 
lutely dependent for existence. Gen- 
eration after generation may occur 
on the same animal. The mite bur- 
rows into the skin, in this respect 
differing from the scab mites. 
Fic. 161.—Sarcoptes seabiet : a, anterior leg; b, The adult mites are flattened, 
ae aS gst eat eee rather circular in outline, and may 
be separated from related forms by 
the character of the feet and by the presence of six short spines or 
thorns on the thoracic portion and fourteen on the abdominal portion of 
the body. 
Eggs are deposited along the burrow as the mite extends its channel 
into the deeper portions of the skin, and as they hatch the young feed 
upon the surrounding tissues, and it is said molt four times before 
Fic. 162.—Sarcoptes scabiei: a, posterior legs of male; b, posterior legs of female (after Furstenberg, 
from Murray). 
maturity. When fully grown they wander around and mate on the sur- 
face of the skin, after which the females begin a fresh burrow. 
Infection with this parasite is accompanied with intense itching dur- 
ing the formation of pustules and inflamed areas, and while in man 
itis usually confined to the base of the fingers and between the knuckles, 
in aggravated cases the whole hand and arm may become invaded. 
