298 A BOOK OF INSECTS 



gules atratulus, of which there is no worker caste. The 

 males and females cohabit with the workers of an entirely 

 different species, known as Tetramorium caespitum. Ex- 

 actly how this state of things originates has not yet been 

 discovered, but it is supposed that a young Aner gates 

 female enters the nest of Tetramorium, destroys the 

 rightful queen, and substitutes herself in place of the 

 victim. If this should prove to be the case, the triumph 

 of the alien must be comparatively short-lived, for when 

 the workers of the Tetramorium community die, she must 

 be compelled to pack or perish. 



In no respect is the genius of the ant more apparent 

 than in the organisation of its commissariat. Not only 

 is food collected with unfailing assiduity and discrimina- 

 tion, but many expedients are adopted whereby a constant 

 supply is assured. Lord Avebury mentions that certain 

 British ants collect the seeds of violets and grasses and 

 carefully preserve them. From some such beginning may 

 have arisen the extraordinary habits of the agricultural, or 

 harvesting ants, of which some twenty species are known. 

 In Southern Italy, members of the genus Aphcenogaster 

 were observed by Mr. J. T. Moggridge to collect systema- 

 tically the seeds of speedwell, nettle, fumitory, and 

 other plants, as well as oat grains. Most of these were 

 gathered from the ground ; but some ants were seen to 

 climb up the stems and detach the seeds, which they 

 either carried away or dropped among their expectant 

 companions below. The seeds are stored in special cham- 

 bers, of which each community is said to possess about 

 one hundred, with a capacity of 20 ounces or more. By 

 some unexplained means, the ants prevent the seeds from 

 sprouting until they are required for food ; but when 

 rations are needed, they allow germination to proceed, so 

 that the store of starch in the seed is converted into sugar. 



