110 



Guide to Arachnida. 



Table-case 



No. 25. 



Sub-order II.— CRYPTOSTIGMATA. 



Acari with the tracheal spiracles situated in the articular 

 sockets of the four pairs of locomotory appendages. The integu- 

 ment is thickly and continuously chitinized, and shows no sign of 

 segmentation. 



This sub-order contains the single family Oribatidae, sometimes 

 known as beetle-mites, on account of their hard, black, shiny 

 integument. They are not parasitic, but live in moss, under stones, 

 etc., in damp places. 



An enlarged drawing of an Oril:)atid mite {Notasjyis hicolor) is 

 on view in Table-case 25. 



Sub-order III.— METASTIGMATA. 



Acari with the tracheae opening by a pair of stigmata, situated 

 above and behind the base of the fourth or fifth or sixth pair of 

 appendages. This sub-order contains two families : Gamasidae, 



Ixodidae. 



Fam. — Gamasidae. 



There is no serrated beak in 

 these mites. 



They live for the most part a 

 non-parasitic life in damp or moist 

 localities, and prey upon organisms 

 smaller than themselves. Many 

 of them are found habitually upon 

 large insects, like beetles, but 

 apparently for the purpose of loco- 

 motion, not of parasitism. Some 

 members, however, are parasitic 

 upon mammals and birds. 

 Fig. 72. 



Gamasus colcoiitratorum (mag 

 Table-case nified). (After Berlese.) 



No. 26. ' 



F AM . — Ixodida c . 



The coalesced basal segments of 

 the appendages of the second pair 

 are produced in front into a cylindrical piercing process, or beak, 

 furnished with recurved teeth. The appendages of the first pair 

 are still pincer-like, but are much modified. 



The Ixodidae, or Ticks, live as temporary parasites upon 

 mammalia, birds and reptiles, whose blood they suck by burying 

 their mandibles and beak in the skin. The females quit their host 



