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THE AMERICAN NATURALIST 



[Vol. XLIII 



Such adaptations to corn as we get glimpses of are 

 almost without exception adaptations to considerable 

 groups of food plants, in which corn is included— some 

 of these groups select and definite, like the families of 

 the grasses and the sedges, to which the chinch-bug is 

 strictly limited, and others large and vague, like the 

 almost unlimited food resources of the larvse of Lach- 

 nosterna and Cyclocephala under ground. These are 

 evidently adaptations established without any reference 

 to corn as a food plant, most of them very likely long 

 before it became an inhabitant of our region, and applying 

 to corn simply because of its resemblance, as food for 

 insects, to certain groups of plants already native here. 



Entomological Ecology of Corn and the Strawberry 

 Corn being, in fact, an exotic or intrusive plant which 

 seems to have brought none— or at most but one 1 — of its 

 native insects with it into its new environment, it will 

 be profitable to compare the entomological ecology of this 

 introduced but long-established and widely cultivated 

 plant with that of some native species which is also gen- 

 erally and, in some districts, extensively grown. 



We may take, for this purpose, the strawberry plant, 

 whose insect visitants and injuries I studied carefully 

 several years ago. About fifty insects species are now 

 listed as injurious to the strawberry, and about twenty 

 of these also infest corn. Two fifths of the known 

 strawberry insects are thus so little specialized to that 

 food that they feed on other plants as widely removed 

 from the strawberry as is Indian corn. On the other 

 hand, six species, all native, are found, so far as known, 

 only, or almost wholly, on the strawberry, at least in that 

 stage in which they are most injurious to that plant. 

 These are the strawberry slug (Emphytus maculatns) : 

 the strawberry leaf-roller (Phoxopteris comptana) —occa- 

 sionally abundant on blackberry and raspberry, to which 

 it spreads from infested strawberry plants adjacent ; two 



1 Diabrotica longicornis Say. 



