52 MECHANICAL FUNCTIONS. 



of this tribe are known under the common appellation of 

 bugs. Most of them fly only in the night, and some of the 

 larger make a deep-toned sound with their wings, so loud 

 as to be heard many rods distant. 



138. The larvae of some of this tribe, in consequence of 

 their living under the ground, and destroying the roots of 

 plants, which serve them for food, are exceedingly destruc- 

 tive to the farmer. The perfect insects also sometimes 

 make terrible desolation among the forest and other 

 trees. 



139. The blind beetle. The melolontha vulgaris, called, 

 also, chafer, blind beetle, or more commonly cock-chafer, 

 is one of these insects. 



140. The larva of this beetle Fi &- 3 8 - 

 is known to farmers under the 



name of the white worm, and 

 is represented by Fig. 38. The 

 eggs of these worms are deposi- 

 ted in the ground by the parent 

 insect, and when first hatched 

 are of very small size. As they 

 grow, they change their skins 

 several times, and at the end of four years, during which 

 time they remain in the earth, they acquire the size 

 represented, having six legs, armed with strong claws, 

 and a reddish head. During its subterranean residence, 

 it lives on the roots of grass, sometimes committing the 

 most deplorable ravages. When their numbers are great, 

 they cut off all the roots of the grass in the richest mead- 

 ows, leaving the turf entirely detached and dead, so that 

 it may be rolled up by the hands like a carpet, without 

 the aid of a turfing knife. Underneath, the soil appears 

 pulverized, and turned into a soft mould, like the pre- 

 pared bed of a garden. In this, the worms are seen 

 coiled up and lying on their backs, generally almost 

 motionless. 



141. Some years since, a poor farmer in Norwich, Eng- 

 land, suffered so much from these worms as to destroy all 

 his hopes, and the authority of that city out of compassion, 

 voted him 25 pounds to assist him under such a calamity. 

 This man and his servant testified, that they had gath- 



