Hydrachnellae 273 



Limnohalacarinae Viets, 1927 

 Genera: 



1. Limnohalacarus Walter, 1917 



a. Limnohalacarus s. str. 



Type. Halacarus wackeri Walter, 1914 



b. Stygohalacams Wiets, 1934 



Type. Stygohalocarus scupiensis Viets, 1934 



2. Hamohalacarus WdAiQY, \92>\ 



Type. Hamohalacariis subterraneus Walter, 1931 



3. Soldanellonyx ^2i\iQr, \9\1 



a. Soldanellonyx s. str. 



Type. Soldanellonyx chappuisi Walter, 1917 



b. Parasoldanellonyx Viets, 1929 



Type. Soldanellonyx parviscutatus Walter, 1917 



Halixodinae Viets, 1927 

 Genus: 



Halixodes Brucker and Trouessart, 1900 

 Type. Agaue chitonis Brucker, 1897 



Enterohalacarinae Viets, 1938 

 Genus: 



Enterohalacarus Viets, 1938 



Type. Enterohalacarus minutipalpus Viets, 1938 



Astacopsiphaginae Viets, 1931 ' • " J 



Genus: 



Astacopsiphagus Wiets, 1931 



Type. Astacopsiphagus parasiticus Viets, 1931 



Discussion: Newell 1947 has summarized the ecological zones of the 

 mites by subfamilies as follows. The halacarids are either predaceous 

 or lichen feeders, and in three genera are parasitic. 



1. Rhomb ognathinae Viets, 1927, is principally intertidal, rarely if 

 ever found in fresh water, and never lives under conditions which pre- 

 clude algal growth. These mites are cosmopolitan. 



2. Actacarinae Viets, 1939, is intertidal, arenicolous, and is never 

 found under conditions which preclude algal growth. It is found in the 

 North Sea. 



3. Lohmannellinae Viets, 1927, is predaceous, either in marine or 

 fresh water, and is probably cosmopoHtan in distribution. 



