102 Psyche [June 



ON SOME NORTHWESTERN ANTS AND THEIR GUESTS. 



By William M. Mann, 

 Stanford University, California. 



These notes are based on a collection of ants and myrmeco- 

 philes made by the writer in Washington and Idaho, during 

 1908-1909, while a student at the State College of Washington, at 

 Pullman. Some collecting had been done previously at Helena, 

 Montana, and six weeks were spent at the Puget Sound Marine 

 Laboratory on Orcas and San Juan Islands, Puget Sound, where 

 considerable collecting was done. 



I am under obligations to Prof. William M. Wheeler of Harvard 

 University, for determining my ants, and to Prof. A. L. Melander, 

 through whom I was given opportunities to visit and collect in a 

 number of localities. This paper was prepared in the Entomologi- 

 cal laboratory of Stanford University. 



In collecting little sifting was done, but traps were used wherever 

 practicable. A piece of board or a fiat stone buried in a mound 

 proved a good means to attract inquilines. 



Solenopsis molesta Say. — Common in vicinity of Pullman and 

 Wawawai, Wash. 



Pheidole oregonica Emery. — Common at Pullman and 

 Wawawai, Wash. At the latter place, four specimens of 

 Cremastochilns knochii were found in a nest. A great many other 

 nests were examined, but no inquilinous beetles were found. 



Aphaenogaster subterranea Latr. subsp. occidentalis 

 Emery. — Many nests examined at Pullman and Wawawai, Wash. 

 During April and the early part of May the Pselaphid Ctenestes 

 pulvereus Lee. was taken commonh', nearly every nest containing 

 one or two. April 10, Prof. A. L. Melander took a number of 

 specimens of an undescribed Bairisus with this ant at Kendrick, 

 Idaho. Several nests were examined and all contained the beetles. 

 A single spcimen of C. -pulvereus was found here also. 



Pogonomynnex occidentalis Cress. — Occurs commonly in 

 the Snake River Canyon at Wawawai, and at Lewiston, Idaho. 



Myrmica rubra L. subsp. brevinodis Emery. — Taken at 

 Helena, Montana. 



