208 THE ECONOMIC IMPORTANCE OF ANIMALS 



the comb. It is now thinner than what we eall honey. To thicken 

 it, the bees swarm over the open cells, moving their wings very 

 rapidly, thus evaporating some of the water. A hive of bees 

 have been known to make over tdrty-one pounds of honey in a 

 single day, although the average 'is very much less than this. It 

 is estimated from twenty to thirty millions of dollars' worth of 

 honey and wax are produced each year in this country. 



Cochineal and Lac. Among other products of insect origin 

 is cochineal, a red coloring matter, which consists of the dried 

 bodies of a tiny insect, one of the plant lice which lives on the 

 cactus plants in Mexico and Central America. Tne lac insect, 

 another one of the plant lice, feeds on the juices of certain trees 

 in India and pours out a substance from its body which after 



treatment forms shellac. Shel- 

 lac is of much use as a basis 

 for varnish. 



Gall Insects. Oak galls, 

 growths caused by the sting of 

 wasp-like insects, give us prod- 

 ucts used in ink making, in tan- 

 ning, and in making pyrogaliic 

 acid which is much used in 

 developing photographs. 



Insects destroy Harmful 

 Plants or Animals. Some 

 forms of animal life are of great 

 importance because of their de- 

 struction of harmful plants or 

 animals. 



A near relative of the bee, 

 called the ichneumon fly, does man indirectly considerable good 

 because of its habit of laying its eggs and rearing the young in 

 the bodies of caterpillars which are harmful to vegetation. Some 

 of the ichneumons even bore into trees in order to deposit their 

 eggs in the larvae of wood-boring insects. It is safe to say that 

 the ichneumons save millions of dollars yearly to this country. 

 Several beetles are of value to man. Most important of these 



An insect friend of man. An ichneumon 

 fly boring in a tree to lay its eggs in 

 the burrow of a boring insect harmful 

 to that tree. 



