ARTHROPODA g 



far north as New Hampshire and Michigan. In the tropics the damage 

 is so serious that in some places all important buildings are being 

 constructed entirely of concrete. In hard wood their main passages 

 usually follow the course of the grain, as shown in Fig. 76. 



Besides the damage done to wood, just noted, many other products 

 are injured; for example: books, Fig. 77; clothing, food, etc., espe- 

 cially if stored in damp, dark, poorly ventilated cellars; shrubs, flowers 

 and nursery stock; and field crops of various kinds. 



As in most cases, "an ounce of prevention is worth a pound of 

 cure," and it is better to protect property against inroads of white 

 ants than to drive them out after they have come. T. E. Snyder, 

 (106) of the U. S. Department of Agriculture gives the following sum- 

 marized recommendations, both for the "prevention" and for the 

 "cure:" 



"How Buildings Should be Constructed so as to be 'White Ant Proof.' 



"Where possible, make the foundation of buildings entirely of stone, 

 brick, or concrete, including stone columns or pillars in the basement to sup- 

 port the floor above; make the walls and flooring in the basement or cellar 

 also of concrete, and lay concrete floors on a giavel base. Fill in and round 

 off points of juncture between concrete walls and flooring so that these will 

 not meet at right angles. 



"Where stone or concrete foundations are impracticable, use timber im- 

 pregnated with coal-tar cieosote. 



"Never completely surround beams with mortar or brick; leave an air 

 space around the beams to permit air circulation. Set beams on stone or 

 on concrete, not in the earth or in moist concrete. Rest the supports of 

 porches or steps on stone or concrete. 



"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 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. 



"In greenhouses, replace woodwork, wherever possible, with iron frames 

 and concrete work. Treat necessary woodwork, before use, with a i per- 

 cent, solution of bichlorid of mercury. 



"How to Eliminate White Ants Already Established in Buildings. 



