2o8 THE FOOD OF ANIMALS 



below. Once secured, the harvest is housed in special ex- 

 cavations or " barns ", of which a single nest possesses about a 

 hundred, holding between them 20 ounces or more. After storage, 

 germination is prevented from taking place until the food is re- 

 quired for consumption, but the way in which this is done has 

 not yet been discovered. To understand the further operations 

 it must be premised that a seed or grain contains a dormant 

 plantlet, together with a store of nutritive material, mostly starch, 

 for its use in the early stages of growth or germination. At the 

 commencement of this process the starch is converted into a form 

 of sugar, which readily diffuses into the developing plantlet. The 

 sweet taste of sprouting malt is due to this cause. Our Ants 

 allow germination to go on till the sugar is produced, and then 

 nip off the sprouts, which would otherwise absorb it. The nest 

 of an allied North African species [A. arenarius) may occupy 

 as large a space as 100 square yards, and extend from 3 to 6 feet 

 into the ground. 



Lincecum and M'Cook have studied an even more remark- 

 able North American Harvesting Ant {Pogonomyrmex barbatus) 

 which not merely collects grain, but subjects it to a process 

 which leads to the same result as the threshing-machines used 

 by human beings. For after the grains and seeds have been 

 carried into the nest the workers strip off their husks, after- 

 wards bearing these to the exterior to be deposited on refuse 

 heaps. 



The Leaf-Cutting Ants {fig. 441) of Tropical America (species 

 of Atta, also known as CEcodoma) are, if possible, even more 



Fig. 441.— A Leaf-cutting Ant ((Ecodomd) Fig. 442.— A Bug which mimics a Leaf-cutting Ant 



carrying a piece of Leaf (enlarged) and its Burden, both in form and colour (enlarged) 



interesting than the harvesting forms. Not content with collect- 

 ing the vegetable food which everywhere abounds in the neigh- 

 bourhood of their dwellings, they practise a species of plant 

 culture which may well be compared with the mushroom-growing 



