The larvæ either resemble caterpillars or are pale, helpless maggots, devoid of limbs, for the welfare of which more or less elaborate provisions are made by the mother insect. Later on a pupa stage is reached, from which the winged adult ultimately emerges. The highest members of the order live in communities comprising several casts.
Ants (Formicidae).—These familiar and intelligent diminutive creatures are perhaps the most interesting of all insects, owing to the extraordinary way in which they have become adapted to a great variety of modes of life. All are social, and a community typically consists of males, females, workers (of one or more kinds), and, it may be, soldiers. The first two are generally provided with wings, though those of the females are soon shed, but exceptions to this occur, and some species may have both winged and wingless individuals of one sex or the other. The first pair of jaws (mandibles) are well or even excessively developed, and possess unusually free powers of movement in accordance with the varied functions they have to perform. In many cases the females (including the workers) are provided with a sting.
Ants hatch out as helpless, limbless larvæ, which have to be fed and carefully attended, either by the fertile females or the workers, as the case may be. Feeding is rather a curious affair, for the nurse possesses a sort of pouch (crop) connected with her gullet, and this is used as a store from which nutriment can be squeezed up into the mouth. Adults can feed one another in the same way, as also the little beetles and other insects which are often found as guests in their communities.
WANDERING ANTS OF
THE TROPICS
These ants are of highly carnivorous habits, and move about in large armies, devouring everything of animal nature that comes in their way. The fact that they are blind, or practically so, does not seem to interfere with their devastations. Some of the forms are common in the hotter parts of South America, while others, the “driver” ants, are well known in Africa, where criminals, it is said, are sometimes tied up in their path, to perish miserably, if speedily.
SLAVE-HOLDING ANTS AND
THEIR SLAVES
Some ants press weaker species of their kind into unmerited captivity. In one familiar instance the relatively large oppressor (Polyergus rufescens) is of reddish color and well endowed in the matter of jaws, while the enslaved species (Formica fusca) is small and dark. Regular slave raids are made from time to time, when, after stubborn resistance, the pupæ and older larvæ of the weaker form are carried away to lead a life of bondage, to which, indeed, they take very kindly. This kind of social economy has indeed become an absolute necessity to the slavers, which have quite lost the power of feeding their own young, while some such species cannot feed themselves.
A most extraordinary state of things occurs in the case of a small kind of ant (Anergates) which possesses no workers of its own, but lives within the communities of another species (Tetramorium cæspitosum) entirely made up of workers.
Some ants, such as the little black species (lasius niger) common in gardens, use as part of their food a sweet fluid that exudes from plant lice (aphides), and keep these insects as we keep kine. The captives are fed, sheltered, and jealously guarded. Fenced enclosures are constructed for them on plants in the vicinity of the nest, with which they are connected by covered roads. During winter the fragile eggs of the plant lice are taken underground and sedulously cared for.
THE HARVESTER ANTS OF EUROPE, NORTH
AFRICA AND NORTH AMERICA