NEW AMERICAN ORIBATOIDEA. 



Bv H. E. EwiNG, 



Arcola, Illinois. 



(With Plates II-VI.) 



The group to which the "beetle mites" belong has been con- 

 sidered by many authors as a family. Mr. A. D. Michael, in his 

 " British Oribatidae," regarded the group as such ; and later, in 1898, 

 in, " Das Tierreich " (Lief. 3. Oribatidae) he divided the family into 

 seven subfamilies. Mr. Nathan Banks in a treatise entitled, "The 

 Acarina or Mites" (Proc. U. S. Nat. Mus., vol. 28, pp. 1-114) has 

 regarded the group as a superfamily which he calls Oribatoidea, divid- 

 ing it into two families as follows : 



Cephalothorax movably attached to the abdomen ; palpi four-jointed. 



Fam. HOPLODERMID.'E. 



Cephalothorax not movable ; palpi five-jointed Fam. Oribatid^. 



I agree with Mr. Banks in calling the group a superfamily. The 

 separation of those forms which have the cephalothorax movably at- 

 tached to the abdomen, from those which have the cephalothorax coal- 

 escing with the abdomen is, I think, very natural. These forms to 

 which he gives the family name Hoplodermidae have many other 

 characters of prime importance which separate them from the rest of 

 the group as will be seen by the characters assigned to each of the 

 groups in the following table. I have also followed G. Canestrini in 

 separating those forms which have abdominal wings from those which 

 do not ; and retain the name he applied to those without the wings, 

 Nothridce. The author gives the following families into which the 

 group may be divided and the characters of each. 



In this paper thirty-one new species are described. The writer is 

 very much indebted to Mr. C. R. Crosby for the specimens collected 

 in Missouri ; to Mr. C. A. Hart for Texas material and to J. D. Hood, 

 C. A. Hart and L. M. Smith for collections in Illinois. 



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