126 CLASS-BOOK OF ZOOLOGY. 



beetles are valuable for medical use ; lobsters and crabs 

 serve as food ; the silk-worm furnishes clothing ; the 

 cochineal, dye-stuff; bees give us honey, and from bees- 

 wax, candles are made. 



§ 528. The injury done by insects is immense. The 

 larvas of the snout-beetles (Curculionites) dwell in the 

 heart of apples, pears, apricots, hazelnuts, chestnuts, 

 peas, and rice, and destroy them. Another larva, called 

 the white or black corn-worm, devours the young shoots 

 of corn, wheat, barley, rye, cabbages, and turnips ; others 

 (Bostrychus) destroy entire forests of pine-wood for miles 

 in extent. 



§ 529. Very great injury is done by caterpillars, which 

 destroy entire orchards ; and still greater by grasshoppers, 

 which, in some countries, appearing in myriads, and 

 devouring every product of the soil, produce famine and 

 pestilence ; as in Egypt, Arabia, and in several countries 

 of Asia and the east of Europe. 



§ 530. Bugs, cockroaches, flies, and parasites, which 

 infest our dwellings or live upon man and other animals, 

 are disgusting and troublesome ; while scorpions, spiders, 

 wasps, and bees are provided with venomous weapons of 

 defence. 



§ 531. Insects, according to the ingenious arrangement 

 of Linnaeus, are divided into seven Orders, viz. : 



1 . Beetles or Chafers, (Coleoptera,) insects with horny 



bodies, and two horny wing-covers ; as the 

 Tumble-beetle. 



2. Bugs, (Hemiptera.) insects with four wings, folded 



together, and of about the hardness of parchment; 

 as Bugs, Locusts, Grasshoppers, and Cock- 

 roaches. 



3. Butterflies, (Lepidoptera,) insects with four ex- 



panded wings covered with colored scales. 



4. Net-winged Insects, (Neuroptera,) those which have 



four transparent, net-woven, or lattice-like wings ; 

 as the Dragon-fly. 



5. Vein-winged Insects, (Hymenoptera.) those which 



have four transparent veined-wings ; as Wasps 

 and Bees. 



