THE CANADIAN ENTOMOLOGIST. 207 



THE MILCH-COWS OF THE ANTS. 



BY THOMAS G. GENTRY, GERMANTOWN, PA. 



The above title, which forms the subject-matter of the present article, 

 is one that has claimed the attention of the most eminent naturalists of 

 all time. Although much has been said and written upon the subject, 

 still there is room for more. As science advances in its onward march 

 new facts are developed ; some of these have a tendency to subvert long 

 established principles, others to confirm pre-existent notions. 



It is well known to naturalists and others that the Aphides secrete, or 

 rather excrete a sweet, viscid fluid, which affords a rich repast for various 

 species of ants. Ordinarily these little creatures are visited by the ants 

 upon the tender branchlets and leaves of plants ; but it has been asserted 

 that they even keep them as human beings do cows. By many this has 

 been deemed partly imaginary. 



Formerly I was disposed to drift with the popular opinion in this 

 particular, but latterly some few facts, which accidentally fell under my 

 notice whilst searching for Carabs, have confirmed me in the opinion 

 that such is the case in at least one species of Formica. 



Whilst exploring a neighboring thicket lately, I was led to raise every 

 stone that lay across or on the side of my path, as experience had 

 taught me that the objects of my search were generally to be found in 

 such concealed places. It was on one of these occasions that I noticed a 

 nest of Formica sanguinea. Disturbed by this unexpected intrusion, the 

 colony soon presented a scene of activity. My interest being at once 

 excited, I decided to change my occupation for the time, and 

 instantly seated myself down upon a slight mound where I could com- 

 mand a view of the nest, and observe the minutest details of ant life. I 

 was not long in perceiving that the community consisted of full-grown 

 neuters, larvae in various stages of developement, and a small species of 

 white Aphis that is ordinarily found adherent to the roots of plants. Not 

 a single male or female was to be seen, they doubtless were occupying 

 at the time the subterranean galleries. The working portion of the com- 

 munity was evidently divided into three classes, each having a separate and 

 distinct part to perform. The first class had the exclusive care 



