126 



PRACTICAL ZOOLOGY 



less man or other animal comes along to which it can attach itself. 



It burrows under the skin, causing itching and sores. Sulphur 



ointment is the best remedy. 

 Face Mites. Face or follicle mites (Fig. 71, C) are rather 



long, slender arachnids that live in the sweat glands or hair folli- 

 cles in the skin of 

 man and some other 

 animals. They are 

 supposed to cause 

 the formation of 

 blackheads. That 

 these mites may have 

 something to do with 

 the spread of leprosy 

 and the origin of 

 cancer has also been 

 suggested. 



Spotted-fever Tick. 

 The most serious 

 disease of man that 

 is spread by ticks 

 in this country is 

 spotted fever. This 

 fever occurs in Idaho 

 and Montana and is 

 supposed to be 

 caused by a minute 

 protozoan parasite. 



The tick transmits these parasites from one animal to another 



when it bites. 



" Red Spiders " on Plants. In several cases plants are badly 



injured by mites. The " red spiders " frequently become so 



numerous in greenhouses, and sometimes outside, that the 



plants whose juices they suck are seriously damaged. These 



mites are very resistant to fumigation, but may be destroyed by 



FIG. 71. Arachnida parasitic on man. 



A, harvest mite or chigger; B, itch-mite; C, fol- 

 licle mite. (From Sedgwick.) 



