CHAPTER XXIV 

 USEFUL INSECTS 



243. Useful Insects. Some insects are useful because 

 they supply food, as the honey-bee. Others supply 

 materials for clothing, as the silkworm. Still others, as 

 we have seen, cause flowers to set fruit by carrying 

 pollen from flower to flower. (See H 140.) There are 

 many species which are especially useful in man's battle 

 with the forces of nature, because they prey upon the 

 injurious insects. 



244. Wasps. There are many kinds of wasps. The 

 common "red wasps" and yellow jackets,"" with their 

 paper nests made out of the fragments of plants, are 

 well known. The mud-dauber is another common wasp, 

 There are many species of wasps that do not live in 

 colonies like the ones just mentioned, but live singly, 

 and are, hence, called "solitary wasps." The wasps are 

 quite closely related to the domestic bees, and bumble- 

 bees, but instead of gathering nectar and pollen for 

 food, as the bees do, they feed on other insects. The mud- 

 dauber fills the mud-cells with the bodies of young 

 spiders, flies, etc., and before sealing up the hole, de- 

 posits an egg. The food for the larva is there ready for 

 it when it is hatched. Wasps are said to catch the biting 

 flies that worry stock, and, especially, the larvae of the 

 boll-weevil. Wasps' nests should not be destroyed 

 except, possibly, in orchards. 



245. Ichneumon Flies, of which there are many 

 kinds, are closely related to the bees and wasps. The 



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