ATTRACTIONS FOR IXSECTS 423 



It is easy to see the load of pollen accumulated in these baskets 

 after such a bee has visited several flowers. Of course the pollen 

 which the bee packs in the baskets and carries off to the hive, 

 to be stored for food, is of no use in pollination. In fact, such 

 pollen is in one sense entirely wasted. But since such bees as 

 have these collecting baskets are the most industrious visitors 

 to flowers, they accomplish an immense share of the work of 

 pollination by means of the pollen grains, which stick to their 

 hairy coats and are then transferred to 

 other flowers of the same kind next visited 

 by the bee. 



398. Nectar and nectaries. Nectar is a 

 sweet liquid which flowers secrete and 

 which attracts insects. After partial diges- 

 tion in the crop of the bee, nectar be- 

 comes honey. Those flowers which secrete 



tj 



nectar usually do so by means of nectar 



glands, small organs situated often near FlG : 3 :f ' f** aild 



pistil of the grape 



the base of the flower, as shown in Fig. 323. (magnified), with a 

 Sometimes the nectar clings in droplets to nectar gland g be- 

 the surface of the nectar glands ; some- tween the stamens 

 times it is stored in little cavities or After Decaisne 

 pouches called nectaries. The pouches at the bases of columbine 

 petals are among the most familiar of nectaries. 



399. Odors of flowers. The acuteness of the sense of smell 

 among insects is a familiar fact. Flies buzz about the wire 

 netting which covers a piece of fresh meat or a dish of sirup, 

 and bees, wasps, and hornets will fairly besiege the window 

 screens of a kitchen where preserving is going on. Many 

 plants find it possible to attract as many insect visitors as they 

 need without giving off any scent perceptible to us, but small 

 flowers, like the mignonette, and night-blooming ones, like the 

 white tobacco and the evening primrose, are sweet-scented to 

 attract night-flying moths. It is interesting to observe that 

 the majority of the flowers which bloom at night are white or 



