WATER MITES, 



147 



CASE 

 X. 



Family HYDRACHNID^ (Fresh Water Mites). 



These, as already said, are merely Trombidii modified to suit 

 the different element in which they live, and with other variations 

 that might be expected from such -a modification. 

 They have the same predominance of bright colour, 

 scarlet and various shades of red preponderating 

 some of them have the same finger and thumb 

 termination of the palpi, although others have it 

 either entirely absent, or nearly so ; but almost all 

 have the last joint hooked so as to serve as an 

 anchor or a grappling hook. Divers of them in 

 one stage or other fasten themselves upon other Pa)i».s ofHydrachna. 

 insects, like the larvae of the harvest mite. They 

 are probably all carnivorous, perhaps living on minute Infusoria; 

 but this we believe is not known with certainty. In all, the tarsi 

 have two claws, with a very short shank, or almost none at all. 



Claw of Atax Bonzi, seen from front and side, retracted and expanded. Copied ffom Claparede. 



Their transformations are very remarkable, but fo*- them and the 

 anatomical details of their structure, we must refer the reader to 

 M. Duges's Memoirs in the " Annales des Sciences Naturelles, 

 Zoologie" 1034. We have no space for these, and can only briefly 

 glance at a few of them as we go along. The whole group being 

 very homogeneous, there is not much room for the creation of 

 genera, but the remarkable difference in the transformations has 

 in many instances supplied this. The following are the more 

 remarkable • — 



K 2 



