When a female, after pairing, does not chance to fall in with any scouting parties of workers, she proceeds without their assistance to found a colony herself in the same manner as is always done by the females of the social wasps and humble-bees every spring. We have repeatedly verified this fact, both by confining a single female after pairing, and witnessing her proceedings, and by discovering in the fields single females occupied in laying the foundations of a future city for their progeny. We lute° met with these single females when they have just begun to form the first cell for tha reception of their eggs ; when the eggs have just been laid ; when the eggs have been hatched; end also when a few workers had been reared to assist in the common labours.
Contrary to what takes place in most insects, the eggs of ants are not, when laid, glued to any fixed place, but are found in parcels of half a dozen or more loosely attached, so that they can be removed at pleasure during the hatching. It has been clown in the ' Penny Magazine' (vol. i., p. GO), by a series of minute observations, that the female earwig moves her eggs with the utmost care from a place which she judges too dry, to one which is sufficiently moist ; and in the same way the female ant, when she founds a colony without assistance, or the nurse-ants in a community, change the situation of the eggs according to the Mate of the weather or of the day and night—a circumstance first observed by Dr. King in tho reign of King Charles 11.
Heat being indispensable to their successful hatching, the eggs are carefully placed during the day near the surface of the nut-hill, but so sheltered from the direct influence of the sun as to prevent the too rapid evaporation of their moisture. During the night, or in cold weather, the eggs are not placed so high, to prevent the escape of the heat which they naturally possess. The attention to the state of temperature occupies much of the assiduity of the female and the nurse-ants.
When the eggs are at length latched (and during this process we have already seen that they enlarge in size), the young grubs are similarly treated with respect to temperature, but greater care is now taken to preserve them from too great- heat, which might prove more injurious than before hatching.
The grubs are fed by the nurse-ants when any of these are in the colony, and by the mother when sho is alone, by a liquid disgorged from the stomach, as is done in a similar way by wasps, humble-bees, pigeons, and canary birds. It consequently requires no little industry meth° part of a solitary female to procure for herself sufficient food to supply nutriment for a brood of perhaps a dozen or twenty grubs, which are insatiably voracious.
When the grubs are full grown they spin for themselves cocoons of a membranous texture, and of a brownish-white colour, not unlike barleycorns in appearauee; and indeed mistaken for these by early observers—a mistake which led to the unfounded notion that ants store up corn for winter provision, though, from their always becoming torpid in the winter, they could have no need of this ; and even were this not so, they never feed on corn, and would probably starve rather than taste it. The authority of Scripture, which has been supposed to countenance the popular notion, is shown by the Rev. Dr. Harris, Messrs. Kirby and Spence, and others, to have no foundation in the sacred text.
The cocoons are treated precisely like the eggs and the grubs with regard to exposure to heat ; and the anxiety of the nurse-ants to shelter them from the direct rays of the sun is taken advantage of on the Continent to collect the cocoons (popularly and erroneously milled anti-eggs) in quantity as food for nightingales and larks. The cocoons of the Wood-Ant are the only species chosen; and in most of the towns in Germany one or more individuals make a living during summer by the business.
In the case of moths, ichneumons, and other insects which spin themselves up in cocoons, the included insect, when the time of its change arrives, is enabled to make its own way through the envelope; but though it would appear, from some observations made by Swammerdem, that ants may, when forced thereto, effect their own disengagement, this is not the usual process. It is the nurse-ants that cut a passage for them with their mandibles, as was first minutely described by Baron de Geer and the younger Huber.
Labours of the Working Ants.—We have already seen that workers or nurse-ants have to labour assiduously in placing the eggs, the grubs, and the cocoons in due degrees of temperature; that they have to feed the grubs by a liquid disgorged from the stomach, and have to dis engage tho insect at its period of change from the envelope of the cocoon. They have also to perform the task of formiug streets, galleries, and chambers for the habitation and protection of the colony, and they exhibit in the work such perseverance and skill as must excite the ndmiration of every observer. Many of their processes, indeed, it is not a little difficult to account for and explain, though these have been very carefully investigated, particularly by the younger Huber, in whose work, and in the' Library of Entertaining Knowledge —Insect Architecture' (p. 254 et seq.), zany be found copious details of the mining, masonry, and carpentry of various species. We shall here give an instance of each of those operations.