220 THE INDUSTRIES OF ANIMALS. 



of the observer. If this incident reveals inconceivable 

 thoughtlessness in one of the members of this serious 

 republic, it also brings to light the judgment, reflec- 

 tion, and decision of vifhich they are capable, as well 

 as a freedom which cannot be found in the works of 

 instinct. 



This Formica fusca sometimes finds itself in the 

 presence of other difficulties. It may happen that 

 the hall to be roofed is too large and the arch too 

 considerable to allow of the cohesion of the materials 

 employed. The insects soon become aware of the 

 existence of this embarrassing state of things and 

 remedy it in various ways, either by hastily con- 

 structing pillars in the centre of the too large room, 

 or by some other method. Ebrard describes an 

 artifice he has seen employed, which shows to what 

 an extent ants can quickly appreciate and take 

 advantage of the most unforeseen circumstances.^ 

 A worker was labouring to cover a large cell ; two 

 prominences, parts of opposite walls, were advancing 

 towards each other, but there was still a space of 

 from twelve to fifteen millimetres between them, and 

 it seemed no longer possible to burden the two sides 

 without risking a general downfall. The little mason 

 was much disturbed. A graminaceous plant was grow- 

 ing near. The ant seemed anxious to take advantage 

 of it, for it went to it and climbed up the stalk. After 

 having examined and devised, it set about curving 

 it in the direction of the edifice. To attain this 

 object, it placed a little mass of moist earth on the 

 extremity of the leaf, and fixed it there. Under the 

 influence of this weight flexion was produced, but 

 only at the end. This could not satisfy the insect ; 



' Ebrard, Etudes de Mmurs, Geneve, 1864, p. 3. 



