DOORWAYS 



genious as simple, to carry off the waters from the ant-hill, 

 to protect it from atmospheric influences and from hostile 

 attacks, and to temper the sun's heat or retain its warmth in 

 the interior of the nest. The heap of materials of which it 

 is composed always takes the shape of a rounded dome, 

 whose base, often covered with earth and pebbles, forms a 

 zone above which the wooden portion of the building rises 

 like a sugar-loaf. 



But this is merely the outer covering of the ant-hill ; the 

 larger portion descends underground to a greater or less 

 extent and is thus out of sight. 



Funnel-shaped avenues, carefully though irregularly con- 

 structed, lead from the roof to the inside of the nest, their 

 number varying accordingly to the population and extent of 

 the colony. The entrance is not always the same width ; 

 sometimes we find one large opening at the top, but usually 

 there are several apertures of similar size around which 

 many narrower passages are placed almost symmetrically, 

 disposed in circles right down to the level of the ground. 



These doorways were necessary to give a free passage to 

 the vast multitude of labourers of which the colony is com- 

 posed ; not only do the insects emerge when it is necessary 

 for them to do so in order to work on the outside of the nest, 

 but differing greatly from other species who gladly remain 

 inside where they are sheltered from the sun, the red wood 

 ants prefer living in the open air, and do not hesitate to 

 carry on the greater part of their operations in our presence. 



If we examine the dwellings of the yellow ant, the black 

 ant, the sanguine ant, the brown ant, etc., we find that the 

 openings are never so wide as to allow their enemies to gain 

 admission easily, or to permit the rain to enter. Their 

 habitations are covered with a dome of earth, closed on all 

 sides ; the only outlet is near the base, and even that is ap- 



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