414 BIOLOGIC EELATIONS BETWEEN PLANTS AND ANTS. 



pass by insensible gradations to a form with an enormous Lead — a sol- 

 dier. The description of their method of harvesting and preserving 

 the grain we must borrow from Moggridge, that acute observer, who, at 

 32 years of age, being forced by phthisis to seek a climate less inclem- 

 ent than that of England, employed his latest strength in studying the 

 ants of the neighborhood of Mentone. 



Often upon uncultivated lands, there called the garrigues, are seen 

 long trains of ants forming two continuous lines hurrying in opposite 

 directions, one going away from the nest, the other toward it. The lat- 

 ter is laden with seed or capsules that the ants are carrying to their 

 hill. 



These files of foraging ants sometimes range to a considerable distance 

 from the nest, seeking the seeds of grasses, peas, and other plants of 

 the garrigues. They collect not only ripe seeds, but also understand 

 how to detach from the plants green fruits. Thus we may see an ant 

 climbing along the stem of a shepherds-purse (Gapsella bursa-pastoris) 

 and, choosing a green pod, disdaining the riper ones which let fall their 

 seeds at the least touch, seize the peduncle of the capsule between its 

 mandibles and, fixing its hind legs firmly as a pivot, twist the peduncle 

 round and round until it is broken off. Then, laden with this burden, 

 it descends, backing and turning as its load demands, down around the 

 stem to reach its nest. In the same manner are gathered the capsules 

 of chickweed (Alsine media) and the nutlets of little labiates such as 

 Calamintha. 



We may frequently see two ants combine for the purpose of breaking 

 the peduncle of a capsule. While one is gnawing the peduncle the 

 other will twist it off; but it seems that their mandibles are never 

 strong enough to sever the peduncle by cutting alone. If grains of 

 hempseed, millet, and oats are scattered in the neighborhood of the 

 nest of the harvester ants, the insects hasten to carry them off, although 

 those seeds are heavy burdens for them. But it often happens that 

 they are deceived as to the quality of the articles they drag to their nest. 

 Thus they may carry off objects not suitable for food; shells, bits of 

 wood, fragments of leaves. If little procelain beads are scattered along 

 the path of a harvesting train the ants will carry them toward their 

 nest. They soon perceive their error, however, for after an hour of this 

 fruitless labor they pass by their false treasures indifferent to them. 



The seeds of a species of fumitory (Fumaria capreolata) are gathered 

 by these harvesters. Now, beside this plant, there fall to the ground 

 little galls inhabited by a small cynipid insect. Deceived by the resem- 

 blance between these galls and the seeds of the plant, the ants add 

 them to their store, quite convinced that they are really seeds. What 

 is the fate of the inhabitants of these galls'? Is there not here to be 

 solved an interesting problem involving mimicry of parasitic origin 1 ? 



The situation of the nests of the Atta harbara is often indicated by 

 the presence of a number of jdants that grow around out of the refuse 



