Chitinous Insects less easily excluded. 1 7 



In contrast with these soft-bodied animals are those 

 insects that have a hard investment of chitin. These 

 move with perfect ease even over very thorny and 

 prickly stems and leaves. Only the terminal joints of 

 their antennse are sensitive to the touch of hard points, 

 their bodies and legs not being easily wounded. But 

 it is precisely among these chitinous insects that many 

 species are to be found whose visits would interfere 

 very prejudicially with the functions of some or other 

 parts of the flower. For in most cases the bodily 

 dimensions of such creatures are not adapted to the 

 general conformation of the flower ; that is, their dimen- 

 sions are so small that, in diving into the recesses of 

 the flower for the nectar there secreted, they would 

 touch neither the anthers nor the stigma. The result 

 therefore of their visits would be that not only would 

 the allurement, that is, the nectar, be taken away from 

 those insects which possess bodies of a suitable size, 

 and thus the advantage be lost which attaches to the 

 visits of such invited guests, but that a further evil 

 would ensue, inasmuch as these little unbidden guests 

 would fin up the bottom of the flower, and so cause a 

 mechanical hindrance, which woiild prevent the larger 

 and welcome insects from pushing their trunks to the 

 bottom of the nectaries. 



On the Muttenjoch, in the Gschnitz Valley, I once 

 saw the small moth, Agrotis cuprea S. V., which works 

 not only by night but also most actively by day, 



