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TEE AMERICAN MUSEUM JOURNAL 



been hollowed out by auts and it is apparent 

 that their biting powers are equal to work- 

 ing in the hardest Avoods. In tunneling, 

 ants are expert, and authentic cases are 

 known of their tunneling under ditches and 

 streams. Indeed a South American ant is 

 said to have excavated a tunnel under the 

 bed of the Parahyba Eiver at a place where 

 it is as broad as the Thames at London 

 Bridge. The nest mounds of ants, entirely 

 the work of their versatile mandibles, are 

 familiar to all. Those made by some tropi- 

 cal species reach an enormous size, but even 

 in the United States, the hills of Formica 

 fusca reach a height of four and one-half 

 feet and a diameter of six. In making the 

 gigantic hills of the tropics, the ants tunnel i 

 from ten to thirteen feet or more below the 

 surface. It goes without saying that this 

 hastens the decay of the rocks. "The im- 

 pression one gets from the work of the ants 

 ... in the tropics, is that they are vastly 

 more important as geologic agents than the 

 earthworms of temperate regions." (Bran- 

 ner, p. 152.) 



Aside from their use in constructing nests, 

 the busy jaws of ants find multifarious uses 

 in the normal round of life. All food is 

 gathered by their aid; the eggs and young 

 are tended with solicitous care; and the 

 queen is groomed and fed; the plant lice, 

 the ant people's cattle, are moved from place 

 to place, and shelters are sometimes built 

 over them; the mandibles take part in most 

 features of the toilet of ants — and they are 

 very clieanly creatures; supernumerary males 

 and the dead are disposed of; often the 

 ground about the nest and long trails lead- 

 ing away from it are cleared of all vegeta- 

 tion and obstructions; and in some species 

 "the soldiers bar the entrances to the nest 

 with their heads, and snip intruding ants 

 in two with their strong mandibles." 2 In 

 Pheidole instabilis "the soldiers have an 

 office for which their abnormally large heads 

 and strong jaws peculiarly fit them. . . . 

 Their heads are so large proportionately to 

 their bodies, that if turned upon their backs 

 they are often unable to right themselves, 

 and if not relieved may die practically 

 standing on their heads. This big-headed- 

 ness, with its corresponding development of 



the jaws . . . has led to a peculiar service. 

 The soldiers act as the communal carvers or 

 trenchers, and crack the shells of the oily 

 seeds and the . . . chitiuous cases of the in- 

 sects which the foragers collect." 3 



All this is mandible work, some functions 

 calling for strength and others for delicacy 

 of action. One domestic phenomenon, in 

 which the mandibles play an interesting 

 part, deserves more extended description. 

 The green wood ant of southeastern Asia 

 (CEcophylla smaragdina) makes its nest of 

 leaves fastened together by a fine white web. 

 The adults, however, do not have the power 

 of spinning silk; that is an accomplishment 

 i:)Ossessed only by their larvae. The edges of 

 the leaves being held together by the jaws 

 of workers, other Avorkers carry in larva 

 which spin fine threads from their mouths. 

 By touching the freshly issuing threads first 

 to one side then the other, in fact using the 

 larvae as shuttles, the worker ants quickly 

 fasten the seam. 



"The assiduity with which ants carry bur- 

 dens, and especially the grain-collecting hab- 

 its of various species inhabiting warm 

 countries, led to their being introduced as 

 £eed-sorters into fairy tales. We find a 

 typical instance of this in the story of Cupid 

 and Psyche. One of the first of the impos- 

 sible tasks imposed upon Psyche by the 

 malice of Venus, was the mixing of poppy, 

 vetch, millet, wheat, and other seeds and 

 grains into a large heap, which Psyche was 

 commanded to sort out, each kind into a 

 separate heap. But an ant who was passing 

 took pity on Psyche, and called all its com- 

 panions to her assistance. They came forth 

 from their habitations in troops, like the 

 waves of the sea, and very soon sorted each 

 kind of grain by itself, and when they had 

 finished the work, they withdrew to their 

 nests." 4 



Among other uses of ant mandibles, fall- 

 ing in the category of advantageous ac- 

 tions, is that of leaping. Leaping seems 

 quite a different function from biting, but 

 as we shall see, it is made possible by the 

 simplest of all the movements of the man- 

 dibles — namely, closing them together. "In 

 Odontomachus, the 'tic-ant' of the tropics, 

 for example, the linear mandibles are in- 



' See article by Professor John C. Branner, en- 

 titled Ants as Geologic Agents in the Tropics, 

 Journ. Geol. Chicago Univ., 8, 1900, p. 151. 



2 Kirby, W. F., Marvels of Ant Life, 1898, p. 137. 



■■' McCook, H. C, A7it Communities, 1909, p. 203. 



^ Kirby. 1898. p. 149. This tale is related in 

 the myth of Eros and Psyche in Apuleius' "The 

 Golden Ass." 



