660 ACARINA. 



blance to the living species. The Eoscorpion carbonarius of 

 Meek and "NVorthen is said by them to resemble closely Buthus 

 Idrsutus from California. The other fossil scorpion is the J/a- 

 zonia Woodiana M. and W., which differs from any known 

 living forms in not having any lateral e} T es. Very different 

 and belonging to a much more degraded and embiyonic type 

 is the Cydophtlialmus Backlandi from the Coal Measures of 

 Bohemia, in which the tail is continuous with the body, being 

 unusually thick. 



ACARINA . 



THE Mites differ from other Arachnids by their oval or 

 rounded bodies, which are not articulated, the cephalothorax 

 being merged with the abdomen ; the mouth-parts are adapted 

 either for biting or sucking, and they breathe by tracheae. 

 They are usually minute in size ; the ticks, which are some- 

 times half an inch in length, comprising the largest forms. 

 They appear first in geological history in the Prussian Amber, 

 where species of Trombidium and Hydrachna occur. 



BDELLIIXE Duges. This inconsiderable family is represented 

 by small mites with long, five-jointed maxillary palpi, and from 

 two to six ocelli, which are sometimes w r anting. The limbs 

 are long and thick. The j^oung closely resemble the adults. 

 The genus Bdella has legs of nearly equal length. B. lonrji- 

 cornis Linn., an European species, is scarlet red, and half a 

 line in length. B. marina Pack, lives between tide marks. 



TROMBIDID.E Leach. The species of this family are red 

 mites, with either claw-like or style-like maxillary palpi, and 

 short mandibles, with the terminal joints scissor-like and op- 

 posed to each other. The genus Tetranyclius has slender style- 

 like maxillae, and two ocelli. The two fore pair of legs arise 

 at a long distance from the hind ones, the first pair being the 

 longest. T. tdarius Linn, the little red mites of our hot- 

 houses spin webs on rose leaves. It is yellowish, with two red- 

 dish yellow spots on the sides, and is one-half a line long. 



