256 AN INTRODUCTION TO ZOOLOGY 



honey cells, but also in drone, worker, and transition cells. Care- 

 ful measurements have shown that the cells are seldom perfectly 

 symmetrical, although in many cases they appear so to our eyes. 

 The honey cells are built with entrances slightly above their bases, 

 so that the honey stored in them will not flow out before it be- 

 comes " ripe" (200). 



THE COLLECTION OF PROPOLIS. "Bee glue," as propolis is 

 sometimes called, is a resinous material collected from buds 

 and crevices of trees. It is transported in the pollen baskets, and 

 is used, as soon as collected, to paint the inside of the hive, to 

 fill up cracks, and to strengthen any loose parts. 



GATHERING POLLEN. Pollen grains are of inestimable value 

 in the bee household. They are very small, of various shapes and 

 colors, and are formed within a part of the flower, known as the 

 anther. The pollen grains contain the male element in the fertili- 

 zation of flowers, and consequently are necessary for the produc- 

 tion of fertile seed. To the bee, pollen is invaluable as a food, 

 and is also used in preparing the cells containing pupae. We 

 have already described the peculiar structures on the legs and 

 other parts of the bee's body used in collecting pollen (p. 236). 

 Upon reaching the hive the pellets of pollen are pried out of the 

 pollen basket by the spur at the termination of the tibia of the 

 middle leg (Fig. 131, D, s), and deposited outside the brood 

 clusters in whatever cells are available usually in worker cells. 

 Pollen is the principal food of the larvae. It is very rich in 

 nitrogenous material, a food element not found in honey, and 

 without which the young would starve. The gathering of pollen 

 by bees has a great influence upon the flowers visited, as is ex- 

 plained in another place (p. 262). 



CARRYING WATER. During warm weather water is sucked up 

 into the honey sac from dew, or brooks and pools, and carried 

 to the larvae in the hive. In cool weather moisture condenses 

 in the hive in sufficient quantities, and, under some conditions, 

 to such an extent as to injure the inhabitants. 



THE MANUFACTURE OF HONEY. Bees do not collect honey from 



