THE MORE IMPORTANT FAMILIES OF ACARI. 



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houses are at least troublesome, and on plants noxious, these creatures are 

 very useful.— The Pterygosomid^, or Gecko Mites, are flat, orange, red or 

 crimson coloured parasites, infesting Geckos.— The TETRONYCHiDiE, or 



Fig. 10. — Tarsotomus parietim(s (Herm.); female; dorsal side; S = stigma. — Original. 



A very useful species. 



Spinning Mites (fig. 11), are slowly moving, green, yellow, orange or red 

 creatures, which are exceedingly noxious to pLants, as they suck their juices 

 and increase considerably in favourable seasons. The red species are 

 commonly known as " Eed Spiders ^' in Germany and in America. They 

 spin beautiful bowers in the angles of the leaf-nerves, but when they are in 

 great quantities and the nights are long and cold, they spin together an 

 extremely fine and shining tissue which envelops whole branches, twigs and 

 leaves. Their legs terminate in four nail-shaped claws ; hence the name of 

 TetronycJius. — The Cheletid^ are quickly running voracious creatures with 

 enormous prehensile maxillary palps (fig. 12). As they suck to death all kinds 

 of mites, noxious to our plants and to our victuals, we must reckon them among 

 our best friends. Like the foregoing Familv they lack stigmata, but possess 

 long membranous peritremata. — The MvoBiiDiE, or Mouse Mites (fig. 13), 

 are sluggish white creatures, which only suck lymph, and may be in some 

 instances very troublesome to small mammals, including bats, as they attach 

 themselves with their lancet-shaped mandibles preferably on tender parts of 

 the skin, e.g. the eye-lids, lips, arm-pits, etc. — The BoELLiDiE, or Snouted 



