188 THE MARVEL OF INSECT LIFE. 



sting. It is an universal rule among sting-bearing 

 insects that the males are perfectly harmless. Unlike 

 the Social Bees, which feed the young grubs, or larvse, 

 until they are about to assume the pupal state, the 

 Solitary Bees form a separate cell for each of the young, 

 fill it with a supply of food which will nourish it until it 

 becomes a pupa, close up the cell, and leave it. 



Chief among them are the Earth-burrowers, many of 

 which belong to the genus Andrena. 



Some of them prefer hard soils, and have especial 

 liking for well-trodden paths, the harder and more stony 

 the better. Their holes are very small, and as they 

 burrow to the depth of eight or ten inches, it is not an 

 easy matter to trace their excavations. 



The best plan is to insert a flexible grass stem into the 

 hole, and dig a funnel-shaped pit, of which the grass 

 stem occupies the centre. At the end of the tunnel will 

 be found a little cell, simply excavated in the earth and 

 filled nearly to the ceiling with pollen. Generally there 

 is only one cell to each tunnel, but occasionally the bee 

 digs several branch tunnels, and places a store of food 

 and an egg in each. Within this dark subterraneous 

 chamber the egg is hatched into a legless grub, such as 

 has been mentioned. It immediately begins to feed, 

 and as soon as it has finished the pollen heap in which it 

 is placed, it changes into a pupa, and subsequently into 

 a perfect insect. 



These bees are very common along the sea-shope, 

 especially where the coast is composed of chalk cliffs 



