338 



habits, etc. The following persons have aided very materially 

 in collecting specimens: Mr. C. A. Hart, systematic entomol- 

 ogist of the State Laboratory of Natural History: Mr. J. J. Davis, 

 assistant to the State Entomologist: Mr. J. L. Pricer, A. M., 

 graduate student in entomology; and Messrs. J. Zetek, R. D. 

 Glasgow, and FT. Glasgow, all students of the University of 

 Illinois. 



Dr. S. A. Forbes has kindly permitted the author to work 

 up the oribatid collections of the State Laboratory of Natural 

 History, in which type specimens of the species described in 

 this paper have been deposited. 



Methods. 



In making collections of oribatids several methods may be 

 employed. It is very desirable that these mites be collected 

 alive, in order that they may be studied before being placed in 

 a preserving fluid. All notes on color and the position of the 

 bristles and pseudostigmatic organs should be made from living- 

 specimens. Individual mites can be very readily transferred 

 on a camel's hair brush to a collecting vial, to be taken to the 

 laboratory and killed. 



Specimens are best killed in hot water or hot alcohol, when 

 they die in an extended position, most favorable for study. 

 While the specimens are still in the alcohol, notes should be 

 made on the shape of the pteroinorphae, the pseudostigmata. 

 and the pseudostigmatic organs, since it is hard to study the 

 form of these parts in the dorsal or ventral view of perma- 

 nently mounted specimens. Mr. Michael suggests the use 

 of dilute acetic acid instead of alcohol as a preservative. 



In order to collect oribatids in large numbers, 1 use with 

 great success a modification of the lierlese method described 

 by Howard in '•Entomological News". Vol. XVII.. 1906. pages 

 49-54. If vegetable debris is passed through a sieve before 

 being treated by the Berlese method, the number and variety 

 of small arthropods that may thus be obtained is surprisingly 

 large. A simple but satisfactory method consists in placing 



