2i 4 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



that cause the disgusting disease known as itch are seldom 

 found except on unclean people. These mites live normally 

 in the skin, often burrowing deep and causing intense itching. 

 Sulphur ointments and other washes are used as remedies, 

 but on account of their burrowing habits these mites are hard 

 to kill. Cleanliness will prevent infection. 



Closely related to the itch-mite of man are several kinds 

 attacking domestic animals, causing mange, scab, etc. The 

 variety infesting horses burrows in 

 the skin and produces sores and 

 scabs, and is a source of very great 

 annoyance. These mites may also 

 migrate to man. Tobacco water 

 and sulphur ointments are used as 

 remedies. 



Horses and cattle and other do- 

 mestic animals are also infested by 

 mites of the species Psoroptes com- 

 munis, which cause the common 

 mange. These do not burrow into 

 the skin, but live on its surface in 

 colonies, feeding on the skin and 

 causing crusts or scabs. The in- 

 flammation causes the animal to 

 scratch and rub constantly, and 



often results in the loss of much of the hair. Single animals 

 may be treated with sulphur ointments or with lime-sulphur 

 mixtures; where several are to be treated, dipping vats should 

 be used. 



The mites, Psoroptes co'mmunis var. ovis, that cause scab in 

 sheep, are among the worst pests that sheep owners have to 

 contend with. Once introduced into the herd they spread 

 rapidly so that the whole flock may soon become infested. The 

 fleece of scabby sheep becomes rough and felted and is easily 

 rubbed or pulled off, often leaving the sheep very ragged and 

 sore. The most satisfactory treatment for scabby sheep is to 

 hand dip them or drive them through vats containing lime and 

 sulphur or tobacco mixtures. 



FIG. 98. Itch-mite, Sar- 

 coptes scabiei, female, dor- 

 sal aspect. (Greatly mag- 

 nified; after Fiirstenberg.) 



