102 (db. a. c. oudemans). notes on acari. 



Classification of Oribatîdae. Tliere are two well separated immed- 

 iately lecogriizable natural groups. The first larger group con- 

 tains animals, which are not capable to roll up themselves; a 

 primitive character The animals of the second smaller group may 

 roll up themselves, as their céphalothorax is movably articulated 

 to the abdomen, and is capable of being folded downward, so that 

 its ventral surface then rests against the ventral surface of the 

 abdomen; a secundary character. Therefore this smaller, secundary 

 group, the VII Phlfiiracarinae, undoubtedly is of younger date, 

 and must be placed at the end of the Orihatidae. 



The primitive lai'ger group of Oribafldae, which are incapable of 

 rolling up themselves, is again divided in two well separated natural 

 groups; the membres of the smaller, second group are provided 

 with movable leg-protecting wings; a secundary character; therefore 

 they are of younger date and must be placed behind the remaining 

 Orihatidae, and before the above mentioned Phthiracarinae. Their 

 name is VI Notaspidmae. 



The primitive, larger group is again broken up in two other 

 natural groups; the smaller of these groups contains membres with 

 one-jointed distally saw-like mandibles, thus these V Serrariinae 

 bear secundary characteis, therefore they are of younger date than 

 the remaining with chelate mandibles, and consequently they must 

 be placed at the end, but before Xhe dihov e meniìomà Notaspidinae. 



The remaining are divided in two groups, of which the younger 

 one, the IV ZetorcJiesiinae, have jumping 4th pair of legs. 



Of the remaining the younger ones, the III Eremaeinae are 

 provided with chitinous blades, or bars, or ridges on the céphalo- 

 thorax, known as lamellae. 



Of the finally remaining Orihatidae the I Camisiiuae are un- 

 doubtedly the oldest more primitive animals, the II Oribatinae of 

 younger date. 



Therefore the following table: 



The animals are incapable of rolling 



1. I up themselves 2 



( They may roll up themselves . , 11 



