SCORPIONS, SPIDERS, MITES AND TICKS 209 



keeper, the funnel-web weavers found in the woods and 

 meadows, and the various orb- weavers are all most interesting 

 and deserve more notice, but as they are of no particular 

 economic importance except as they destroy noxious insects, 

 they will not be discussed further here. The best book about 

 American spiders is "The Spider Book" by Professor J. H. 

 Comstock. 



FIG. 95. Web of a grass spider, Agalena sp. (Reduced.) 



TICKS AND MITES (ORDER ACARINA) 



From an economic standpoint the mites and ticks, consti- 

 tuting the order Acarina, are by far the most important mem- 

 bers of this class. The body is very compact, the cephalo- 

 thorax and abdomen being closely fused. This character 

 will serve to separate them from the spiders, the young of 

 which might be mistaken for mites. 



Ticks. The ticks are all comparatively large, that is, they 



are large enough to be seen with the unaided eye, even in their 



younger stages, and some grow to be half an inch long. The 



young when first hatched have only six legs but after the first 



14 



