CHIGGERS — FARRELL 227 



relationship is not necessarily implied in these groupings. But, 

 to quote Simpson again, "Similar animals living in adjacent areas 

 are likely to be more closely related than animals, even equally 

 similar animals, widely separated ... in fact, animals clearly 

 cannot have common ancestry without also having common geo- 

 graphic origin." On this basis the forms within the "rubra" 

 group are obviously related. The species of the "blarinae" group, 

 excepting possibly E. sciuricola, appear to be related, with E. 

 carolinensis and E. ohioensis having closer affinities. However, 

 not enough is known of the species and their distributions to at- 

 tempt any further genetic groups. 



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