PROBLEMS OF SPIDERS, MITES, AND TICKS 165 



of leaves. So minute are they that a single one is scarcely 

 visible to the naked eye, and they are often not noticed until 

 the plant is badly infested. 



They pierce the surface of the leaf and suck its juices, and 

 very soon the plant begins to appear yellow and sickly. When 

 it is practicable the garden hose will exterminate these pests. 

 Under other conditions spraying with fish oils or soap solution 

 is effective. 



Clover mite Bryobia pratensis. As the name indicates, these 

 mites are found chiefly upon clover, but also on apple and 

 peach trees, cottonwoods and arbor vitse, and even on boards, 

 stones, and fences. During the fall and winter they appear 

 also on plum, almond, poplar, and elm trees, and frequently 

 leave vegetation entirely and become very troublesome in 

 houses. 



Of species found upon animals, there are some which can- 

 not be considered a real menace to health, yet they are ex- 

 tremely irritating and troublesome. The most common of these 

 are harvest mites and wood ticks, the former being one of 

 the smallest of mites, a mere pin point of red, and the latter 

 one of the largest of ticks, reddish brown, a quarter of an 

 inch in length and swelling, as it feeds, to the size of an olive. 



Harvest mite Trombidium holosericeum. When in the larval 

 stage, these are the "chiggers" of the Middle States. During 

 early summer harvest mites will be found on grasslands and 

 sandy slopes, or in the woods. They can be seen most easily 

 in July, when the eggs are being laid, and that is the time 

 also when they begin to attach themselves to any passing 

 animal. The creatures of the woods, especially moles and 

 hares, are sometimes literally infested with them, and dogs, 

 cats, horses, and cows often show signs of intense itching 

 from them. In some localities there are few people who have 

 not felt their presence. Sulphur ointment or friction with a 

 cloth dipped in benzine or strong alcohol will give speedy 



