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Indiana University Studies 
cies, one becomes convinced that accurate information on the 
variability or constancy of species over wide areas, the ex- 
tent of host and geographic isolation between related species, 
the correlation of biologic and structural facts, and the at- 
tainment of sound conclusions as to the affinities of species 
within any group and consequent interpretations of species 
and biologic phenomena cannot emanate from anything short 
of the most extensive data that modern facilities can provide. 
