THE CANADIAN ENTOMOLOGIST. 2017 
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, larvee 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 
