THE ORCHIDS OF NEW ENGLAND. 63 



"All dull yellow (dirty-yellow, brownish-yellow, yellowish- 

 white) flowers," says Muller * giving a long list of genera which 

 includes Neottia, "are entirely or almost entirely avoided by 

 beetles ; closely allied white flowers are visited by beetles, more 

 or less to their injury ; and brightly colored flowers, even though 

 they are scentless and offer no honey, or none that is accessible, 

 attract beetles in numbers. If (as he supposes) beetles are only 

 or mainly attracted to flowers by bright colors, dull yellow must 

 be an advantageous color for plants with freely exposed honey, 

 protecting them from these injurious guests. And the fact that 

 dull yellow colors only occur in flowers with exposed honey 

 lends support to this view." Speaking in another place \ of 

 the effect of conspicuousness in inducing insects' visits, he says: 

 " . . . those insects whose bodily organization is least 

 adapted for a floral diet are also least ingenious and skilful 

 in seeking and obtaining their food, so that with anthophilous 

 insects intelligence seems to advance pari passu with structural 

 adaptation," hence, " short-lipped insects, little or not at all 

 specialized for a floral diet, can usually only find fully exposed 

 honey, such as Listera (and others) afford ; honey still easily 

 accessible but not directly visible to them is passed by." 



He says again: "Insects in cross-fertilizing flowers endow 

 them with offspring which, in the struggle for existence, van- 

 quish those individuals of the same species which are the off- 

 spring of self-fertilization. The insects must, therefore, operate 

 by selection in the same way as do unscientific cultivators 

 among men who preserve the most pleasing or most useful 

 specimens, and reject or neglect others. In both cases, selec- 

 tion in course of time brings those variations to perfection 

 which correspond to the taste or needs of the selective agent." 

 As insects became more skilful and intelligent, flowers became 

 more varied in color, more complicated in structure, etc. "The 



* Fertilization of Flozuers, p. 574. f Page 571. 



