Cuap. I. FUNCTIONS OF ANTS. 15 
did with the hard dry grains of mandioca I was never able to ascertain, 
and cannot even conjecture. The meal contains no gluten, and 
therefore would be useless as cement. It contains only a small relative 
portion of starch, and, when mixed with water, it separates and falls 
away like so much earthy matter. It may serve as food for the sub- 
terranean workers. But the young or larvz of ants are usually fed by 
juices secreted by the worker nurses. 
Ants, it is scarcely necessary to observe, consist, in each species, of 
three set of individuals, or, as some express it, of three sexes— 
namely, males, females, and workers; the last-mentioned being un- 
developed females. The perfect sexes are winged on their first attaining 
the adult state ; they alone propagate their kind, flying away, previous 
to the act of reproduction, from the nest in which they have been reared. 
This winged state of the perfect males and females, and the habit of 
flying abroad before pairing, are very important points in the economy of 
ants ; for they are thus enabled to intercross with members of distant 
colonies which swarm at the same time, and thereby increase the vigour 
of the race, a proceeding essential to the prosperity of any species. In 
many ants, especially those of tropical climates, the workers, again, are 
of two classes, whose structure and functions are widely different. In 
some species they are wonderfully unlike each other, and constitute 
two well-defined forms of workers. In others, there is a gradation of 
individuals between the two extremes. The curious differences in 
structure and habits between these two classes form an interesting, but 
very difficult, study. It is one of the great peculiarities of the Saiiba ant 
to possess ¢hree classes of workers. My investigations regarding them 
were far from complete; I will relate, however, what I have cbserved 
on the subject. 
When engaged in leaf-cutting, plundering farinha, and other opera- 
tions, two classes of workers are always seen (Figs. 1 and 2, page 12). 
They are not, it is true, very sharply defined in structure, for individuals 
of intermediate grades occur. All the work, however, is done by the 
individuals which have small heads (Fig. 1), whilst those which have 
enormously large heads, the worker-majors (Fig. 2), are observed to be 
simply walking about. I could never satisfy myself as to the function 
of these worker-majors. They are not the soldiers or defenders of the 
working portion of the community, like the armed class in the Termites, 
or white ants ; for they never fight. The species has no sting, and does 
not display active resistance when interfered with. I once imagined 
they exercised a sort of superintendence over the others; but this 
function is entirely unnecessary in a community where all work with a 
precision and regularity resembling the subordinate parts of a piece of 
machinery. I came to the conclusion, at last, that they have no very 
precisely defined function. ‘They cannot, however, be entirely useless 
to the community, for the sustenance of an idle class of such bulky 
individuals would be too heavy a charge for the species to sustain. I 
think they serve, in some sort, as passive instruments of protection to 
the real workers. Their enormously large, hard, and indestructible 
heads may be of use in protecting them against the attacks of in- 
sectivorous animals. ‘They would be, on this view, a kind of “ pieces 
