BEES, ANTS, AND WASPS. 51 



the wax away as fast as it is secreted and build it up 

 into honeycomb. The sting serves as a means of de- 

 fense. The barbs on the lancets account for the fact 

 that the sting is -so frequently found in the wound, and 

 the fact that the poison is an acid indicates that am- 

 monia or a solution of soda in water, applied quickly, 

 is a remedy, because either of these will neutralize an 

 acid. 



The bumblebee gathers honey especially from red 

 clover and from thistles. The tongue of the hive 

 bee is too short for the tubes of these flowers. When 

 a bumblebee visits many flowers of clover in succes- 

 sion, some of the pollen of one flower, by sticking to 

 the hairy tongue, is brought into contact with the 

 stigma of another flower. In this way bumblebees 

 bring about cross fertilization of the flowers. This 

 cross fertilization is necessary to the continuous pro- 

 duction of red clover. Without it, very little seed 

 will be produced. Frequently two crops of clover are 

 produced in one year. The first crop is usually cut 

 for hay. It has very little seed, as there are few 

 bumblebees so early in the year. The second crop 

 has an abundance of seed, as there are many bumble- 

 bees late in the season. 



When clover was introduced into Australia, it pro- 

 duced no seed, and the fields had to be seeded every 

 second year with imported seed. But bumblebees were 

 introduced, and now the clover produces plenty of seed. 



Other insects besides bees aid in the cross fertiliza- 

 tion of plants. Wasps, butterflies, rnoths, and flies of 

 certain families, fertilize different kinds of flowers. 



The bumblebee is colored yellow and black, a very 

 conspicuous combination, and it is frequently seen on 

 clover blossoms, which furnish a contrast that is even 

 more conspicuous. -The bee, then, is not concealed by 

 its color. The color of the bee is said to be a warn- 

 ing color. It is a danger signal to other animals. 



