ORDER ACARINA 



25 



features, particularly in their web-making habit and in their 

 achiptation for the cajrture of prey. They are distinctly 

 carnivorous in habit and may be considered useful, since 

 the majority of them capture insects, and the kinds of 

 insects captured are quite generally such as are detrimental 

 to man. In general, therefore, spiders sliould be left unmo- 

 lested and their insect-feeding habits utihzcd in the reduc- 

 tion of injurious insects. 



Fig. 4. — The common red spider (Tetranychus himaculatus) : a, adult; 

 h, palpus; c, claws; n, greatly enlarged; h, c, still more enlarged. (After 

 Banks. From Bur. Ent., U. S. Dept. Ag.) 



Order ACARINA. 



These are commonly known as mites, ticks, scab insects, 

 mange insects, etc., and are in general distinguished by 

 having no prominent separation between the different 

 regions of the body, the head, thorax, and abdomen, forming 

 one closely connected structure. They haxe eight legs, 

 except in the early stages, when there are but six; the 

 eyes are often small or obsolete, the spiracles reduced to 

 one pair, sometimes apparently wanting; the moutli parts 



