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THE AMERICAN NATURALIST. [Vol. XXXVI II. 



conclusions : and as the matter stands, I am well aware of the 

 circumstantial nature of much of it and of the many possibili- 

 ties of wrongly interpreting the facts. However, I have been 

 collecting and studying other species of littoral Coleoptera in 

 the Great Basin, with a view to further prosecution of the prob- 

 lem, and find much in corroboration. It is evident that the 

 same general law is followed in the variations of Tanarthrus, 

 and I hope also to demonstrate a parallelism in certain Carabidae 

 and Histeridaj which are associated with it. 



