The Entomological Society of America 



Volume X JUNE, 19 17 Number 2 



A SYNOPSIS OF THE GENERA OF BEETLE MITES WITH 



SPECIAL REFERENCE TO THE NORTH 



AMERICAN FAUNA 



By H. E. EwiNG, Iowa State College, Ames, Iowa. 



The beetle mites constitute, it is believed, a natural group of 

 the order A carina which, because of its close affinities with some 

 of the other groups of mites, is rather hard to limit or define 

 properly. As considered here, the group includes only those 

 mites which possess, in addition to a hard, chitinous exo- 

 skeleton, a pair of modified setas on the posterior dorsal aspect 

 of the cephalothorax, known to specialists as the pseudostig- 

 matic organs. Thus limited, the beetle mites have been 

 recognized by some workers only as a family, by others as a 

 superfamily, j,nd by several of our foremost authorities as a 

 sub-order. Michael in his treatise on the groups con- 

 sidered it as a family, the Oribatidce, which he divided into 

 seven subfamilies. Banks has considered the group as a 

 superfamily, Oribatoidea, which formerly he divided into 

 two families, Hoplodermidce and Oribatid<je. Recently he has 

 included the family Labidostommatidce- also in the super- 

 family, but this family would not be included in the group 

 as just defined by the writer. Oudemans regards'^ the group 

 as one of the twelve of his subdivisions of the whole order, and 

 gives to it the name of do stigmata. The present writer in 

 1913, gave a classification of the Acarina^ in which the tarso- 



1 Michael, A. D. Oribatidce. Das Tierreich, Lieferung 3, 1898. 



2 Banks, N. The Acarina, or Mites. Report No. 108, U. S. Dept. Agric., 1915. 

 ' Oudemans, A. C. A Short Survey of the More Important Families of Acari. 



Bui. Entom. Research, Vol. I, pp. 105-119, 1910. 



4 Ewing, H. E. New Acarina, Part I. Bull. Amer. Mus. Nat. Hist., Vol. 

 XXXII, Art. V, pp. 93-121, 1913. 



117 



