REVISION OF NEARCTIC TERMITES. 97 



the basement or cellar also of concrete, and lay concrete floors on a 

 gravel base. 



Lay basement window sills and frames over concrete and do not 

 allow the woodwork to come in contact with the ground. Never 

 sink untreated timber in the ground or in moist concrete; let there 

 be no untreated wood in contact with the ground through which the 

 termites may come up from subterranean galleries. 



Complete dryness of the foundation and basement walls and flooring 

 is an important means of rendering buildings safe from attack; 

 therefore provide for air spaces between the ground and wooden 

 flooring and lay concrete floors on a gravel base. 



Since these termites always require access to damp earth, shut off 

 this source of moisture, and the insects will not be able to extend the 

 galleries farther and will perish. By shutting off termites (already 

 in the wood) from the source of supply of moisture in the ground, they 

 will die out, since they can not live without moisture. It is not 

 necessary to do anything more to kill them; the insects will die 

 absolutely when the infested beams are disconnected from the earth. 

 In military parlance: Shut off these termites from their base — that is, 

 moisture supply in the earth — and the vanguard, no matter how great 

 in numbers, infestmg the timbers, will soon dry up. This must be 

 emphasized to owners of infested buildings, since tiiis knowledge will 

 save time and expense, especially in case of old frame buildings, 

 where extensive repairs would be unwarranted. For example, if the 

 source of ingress to the building were shut off by disconnecting the 

 untreated foundation timbers from contact with the soil, the termites 

 win die in the other woodwork, furniture, and stored material in the 

 building, even if they had penetrated to the second or third floors. 

 Furthermore, these timbers need not be removed or replaced unless 

 structurally seriously weakened; the termites will dry up. 



Termites also injure living trees, shrubs, field crops, nursery stock, 

 and flowers, both in gardens and in greenhouses. Much injury by 

 termites can be prevented by clean cultivation and proper horticul- 

 tural management. Injury is more common in the new soil of 

 recently cleared woodland, containing old decaying stumps, wood, or 

 much leaf mold. Fence posts should be treated with coal-tar creosote. 

 Old boards or wood should not be allowed to lie on the ground near 

 fruit trees or in gardens. Prunings should not be left on the ground 

 but should be burned. Where termites are destructive do not use 

 animal manure. 



Care should be taken that living trees should not be scarred at the 

 base. 



In case of species of termites which are not wood borers but are sub- 

 terranean in habit and injure living vegetation, as species of Ami- 



