HYMENOPTERA. 455 



form of a reversed cone. The labrum of the neuters is large, cor- 

 neous, and falls perpendicularly under the mandibles. 

 These Hymenoptera compose the genus 



Formica, Lin. 

 Or that of the Ants, so highly celebrated for their foresight, and so well 

 known, some by their depredations in our houses, where they attack our 

 sugar and preserved viands, communicating to them at the same time a 

 musky and disagreeable odour, and others by the injury they do to our 

 trees, by gnawing their interior in order to form domicils for their colonies. 



The abdominal pedicle of these Insects is in the form of a scale or knot, 

 either double or single, a character by which they are easily recognized. 

 Their antennae are geniculate, and usually somewhat largest near the extre- 

 mity; the head is triangular, with oval or rounded and entire eyes, and the 

 clypeus large; the mandibles are very strong in the greater number, but 

 vary greatly as to form in the neuters; the maxillae and labium are small; 

 the palpi are filiform, and those of the maxillae the longest; the thorax is 

 compressed laterally, and the almost ovoidal abdomen furnished, in the fe- 

 males and neuters, sometimes with a sting, and sometimes with glands that 

 secrete a particular acid called ybrmic. 



They form communities which are frequently extremely numerous. 

 Each species consists of three kinds of individuals: males and females which 

 are furnished with long wings, less veined than those of the other Hymen- 

 optera of this section, and very deciduous; and neuters, destitute of wings, 

 which are merely females with imperfect ovaries. The males and females 

 are merely found within the domicU in transitu. They leave it the moment 

 their wings are developed. The females wander to a distance from 

 their birth-place, and having detached their wings by means of their feet, 

 found a new colony. Some of those however which are in the vicinity of 

 the ant-hills are arrested by the neuters, who force them to return to their 

 domicil, tear off their wings, prevent them from leaving it, and force them 

 to deposit their eggs there — it is thought, however, that they are violently 

 expelled the moment that operation is effected. 



The neuters, which are distinct, not only by the want of wings and ocelli, 

 but also by the size of their head, the strength of their mandibles, their 

 more compressed and frequently knotted thorax, and their proportionally 

 longer legs, have the sole charge of all the economy of the habitation, and 

 the rearing of the young. The nature and form of their nests or ant-hills 

 vary according to the particular instinct of the species. They usually es- 

 tablish it in the ground; in its construction some only employ particles of 

 earth, and almost entirely conceal it; others seize on fragments of various 

 bodies and with them raise conical or dome-like hillocks over the spot in 

 which they are domiciliated. Some establish their dwelling in the trunks 

 of old trees, the interior of which they perforate in every direction in the 

 manner of a labyrinth, in which the detached particles are also employed. 



