14 INSECTS INJURIOUS TO VEGETATION. 



from the latter find a sufficient quantity of food to supply all their 

 wants within the larger eggs they occupy. The ruby-tails {Chrys- 

 ididcB), and the cuckoo-bees {HylcBus, Sphecodes, Nomada, Melecla, 

 Epeoliis, Calioxys, and Stelis), lay their eggs in the provisioned nests 

 of other insects, whose young are robbed of their food by the earlier 

 hatched intruders, and are consequently starved to death. The wood- 

 wasps (Crabroiiidce), and numerous kinds of sand-wasps {Larradce, 

 Bernhicidce, Spegidce, PompilidcB, and Scoliadce)^ mud-wasps (Pe- 

 lopceus), the stinging velvet-ants {Mutilladce), and the solitary wasps 

 {Odynerus and Eumenes), are predaceous in their habits, and pro- 

 vision their nests with other insects, which serve for food to their 

 young. The food of ants consists of animal and vegetable juices ; and 

 though these industrious little animals sometimes prove troublesome 

 by their fondness for sweets, yet, as they seize and destroy many 

 insects also, their occasional trespasses may well be forgiven. Even 

 the proverbially irritable paper-making wasps and hornets {Polistes 

 and Vespa), are not without their use in the economy of nature; for 

 they feed their tender offspring not only with vegetable juices, but 

 with the soft parts of other insects, great numbers of which they seize 

 and destroy for this purpose. The solitary and social bees {Andre- 

 nadce and Apidce) live wholly on the honey and pollen of flowers, 

 and feed their young with a mixture of the same, called bee-bread. 

 Various kinds of bees are domesticated for the sake of their stores of 

 wax and honey, and are thus made to contribute directly to the com- 

 fort and convenience of man, in return for the care and attention 

 afforded them. Honey and Wax are also obtained from several spe- 

 cies of wild bees, {Melipona, Trigona, and Tetragona), essentially 

 different from the domesticated kinds. While bees and other hymen- 

 opterous insects seek only the gratification of their own inclinations, in 

 their frequent visits to flowers, they carry on their bodies the yellow 

 dust or pollen from one blossom to another, and scatter it over the 

 parts prepared to receive and be fertilized by it, whereby they render 

 an important service to vegetation. 



7. — DiPTERA (Mosquitos, Gnats, Flies, ^c). Insects with 

 a horny or fleshy proboscis, two wings only, and two knobbed 

 threads, called balancers or poisers, behind the wings. Transfor- 

 mation complete. The larvae are maggots, without feet, and 

 with the breathing-holes generally in the hinder extremity of the 

 body. Pupae mostly incased in the dried skin of the larvae, some- 



