Beneficial Insects 



Fig. 29. Nest of a Mud-dauber taken from Rafter of an Out-building 



development of this joint suggested the name " thread-waisted wasps" 

 by which they are commonly known. 



Many of these species build large many celled nests of mud on the 

 beams of outbuildings and about farm machinery stored under imple- 

 ment sheds (Fig. 29, Page 135). 



The cells of these nests are provisioned with spiders and caterpillars, 

 upon which the young wasps feed. 



After dry spells these wasps are common objects about mud puddles 

 near wells or after showers, where they secure the mud required in the 

 construction of their nests. 



(b) SOLITARY WASPS 



(Fig. 15, Plate VI. Page 20) 



These insects, many species of which resemble the fiery tempered 

 yellow jackets, are peculiarly subject to persecution because of this 

 resemblance. 



Some of the members of this family are masons, building their nests 

 of mud; some are miners, digging tunnels in the earth in which their 

 young pass through the stages of their development ; and still others are 

 carpenters, cutting out tubular nests in wood, and partitioning these off 

 into cells with mud. 



One species (Fig. 15, Plate VI, Page 21) has already been mentioned 

 in connection with the sugar beet webworm (See page 44), and its bur- 

 row figured on page 78 (Fig. 14). 



Another species builds a jug-shaped nest, which is attached to the 

 stem of some plant, and provisions it with small caterpillars. 



B. PARASITIC INSECTS 



While the predacious insects do much to keep down the enemies of 

 cultivated crops their work is not so effective as that of the true parasites, 

 such as the Ichneumon-flies, Braconids, and Chalcis-flies. 



135 



