INSECTS, HARMFUL AND OTHERWISE 



225 



flower be pollinated, not with its own pollen, but with that 

 of some other flower of the same sort, better seed will be 

 formed. It seems to be the aim of nature to bring about 

 cross-pollination, as this is called, in one way or another. 

 And one way is to utilize insects. 



It may be set down as a general rule that all flowers that 

 have bright colors, nec- 

 tar, and perfume are in- 

 sect pollinated. The 

 colors and odors attract 

 the insects, and they like 

 to drink the nectar. 

 The pollen also is eaten 

 by many insects. The 

 insects travelling about 

 from flower to flower 

 carry, not intentionally 

 but accidentally rather, 

 pollen from the stamens 

 of one flower to the pistil 

 of another. 



Plants have developed special structures, that aid materially 

 in cross-pollination or make self-pollination impossible. 



In the common sage the anthers are hinged at the middle to 

 their filaments, and they mature before the stigma of the same 

 flower. A bee trying to get at the nectar in the bottom of the 

 flower strikes the lower part of the lever anther, which turns 

 down and strikes the bee on the back, dusting it with pollen. 

 The dusted bee then goes to another, perhaps older flower, 

 with withered anthers but mature and opened stigma. The 

 style in this flower is elongated, and the stigma held right 



FIG. 75- Butterflies and Bumblebees Like Clover 

 Blossoms. 



