ACAEINA OR MITES. 119 



tinged witli red. Closely related to these are the liarvest 

 Bugs (fig. 49), -which are generally of a brilliant colour, and 

 may be found under stones, earth, 

 &c., and sometimes, in some of their 

 stages, as very noxious human and 

 animal parasites. 



(ii) The Bdellidm or Snouted Mites 

 can be told by the long snout and 

 similar brilliant colouring of the 

 body. Some are parasites on insects. 



(iii) The Gamasidm (fig. 52), some 

 of which are also parasitic on animals 



T T . T .. ,, T Pid, 4!t. — Harvest BiTfi (Tro?)!- 



and birds, have usually some modi- udmm iwiosericmm). 



fication of the second pair of legs to Adult of the Harvest Bug. 



,.,..,,, (X 10 times.) 



distinguish them. 



(iv) The Ixodiddi (fig. 54) or Ticks can always be told by 

 their leathery sliin and by having a shield on the back behind 

 the head. 



(v) The Oribatidce have a hard, chitinous, more or less 

 shiny skin, and are known as Beetle Mites. These are often 

 very beneficial (fig. 59). 



(vi) The Acaridw, colourless and nearly transparent. 



(vii) The Sarcoptidce (fig. 56) are the parasitic forms that 

 produce scab, scaly leg, &c., and have a more or less transverse 

 wrinkled skin and long suckers on some of the feet. 



(viii) The PhytoptidcB (fig. 60) or Gall Mites, living in plants, 

 are all minute and transversely wrinkled. They have only four 

 legs, the two hind pairs being reduced to simple bristles. The 

 mites live in the buds and leaves of plants, and produce galls 

 and blisters. 



Family Trombididse. — The Eed-spider of the hop, Tetrany- 

 chus malvce, may be taken to exemplify this family. They are 

 extremely variable in colour, some being green, others rusty-red, 

 others almost white and transparent ; often dark specks are seen 

 upon them, and in not a few instances brown individuals may 



