No. 509] ECOLOGY OF INDIAN CORN PLANT 291 



of the strawberry root-worms -the larva* of Tupophorus 

 aterrimus and of Scelodonta nebulosus; the strawberry 

 crown-borer (Tyloderma fray aria')) and the strawberry 

 aphis (Aphis forbesi). 



Not even one of this considerable list exhibits, so far 

 as I can see, any special structural adaptation to life on 

 the strawberry plant. The two root-worms mentioned, 

 for example, are no better fitted to feed on strawberry 

 roots than is a third strawberry root-worm— the larva of 

 Colaspis brunnea, which lives on the roots of corn and 

 timothy also. Empht/tits maadatns might feed, for all 

 the structural peculiarities which one can see, on the 

 leaves of roses as well as does the common slug- or false- 

 worm of those shrubs— and so of the others of the list. 

 Even the strawberry crown-borer, which lives in all 

 stages solely on that plant, might, so far as structure and 

 life history are concerned, feed and develop in any other 

 thick-rooted perennial. The difference seems to be one 

 of habit or preference solely, and not of structural 

 adaptation. 



Our impressions of the extent, nicety and frequency 

 with which insects and plants are mutually adapted are 

 indeed commonly much exaggerated, owing to the fact 

 that our attention is especially drawn to notable cases of 

 curious, precise or particularly advantageous adjustments 

 between organisms, while no general study is made of 

 the entire system of relations obtaining between all the 

 members of an associate group, varying widely, as these 

 do, in respect to the intimacy, importance and exelusive- 

 ness of the association. For this same reason, m part, 

 we ordinarily have no accurate idea of the relative fre- 

 quency and primacy of structural, or static, adaptations 

 —particularly obvious, especially interesting, and seem- 

 ingly ingenious, as they often are -and of those more 

 obscure adaptations of preference, behavior, habit and 

 the like, which, taken together, we may call dynamic. 



