260 



HENRY C. MCCOOK. 



sketch as the work advanced, recording at the same time the changes. 

 Thus ray outline grew upon the paper as the work grew upon the 

 ground. 



Building Galleries.— Fig. 1 represents a covered way or gallery 

 G inches long, which started on the foundation 3 or 4 inches below 

 the surface of the field, and ran up toward the half-cone at an angle 

 a little less than 45*^. When first seen it was an open gallery or 

 ditch, and was observed until it was entirely covered over except one 

 door or round hole near the top. The work progressed by the con- 

 tinuous addition of the earth pellets to the outer edge. The pellets 



Fig. 1. — Covering Galleries. (1), horizontal gallery ; (2), vertical gallery. 



were carried in the mandibles of the ants, and were usually pressed 

 into position. The springing of the arch was plainly seen, the two 

 sides slowly approaching each other in irregular lines as shown at a, a. 

 Gradually two points drew near and nearer, until they well-nigh 

 touched. It was quite exciting to watch now the delicate manipula- 

 tion of the architects. Here comes a worker with pellet of larger 

 size J she climbs the arch, reaches over, holding the while by her hind 

 feet, and drops the ball of soil into the broach. The bridge is made. 

 And now with surprising rapidity it is widened until the roof of the 

 arch assumes the appearance indicated at i, h. Circular openings 



