424 



INSECTA. 



Their antenna- are always geniculate, and the ligula is small, rounded and 

 concave, or cochleariform. 



Some form communities in which we find three kinds of individuals, of 

 which the males and females are winged, and the neuters apterous. In the 

 two last the antennae gradually enlarge, and the length of their first joint is at 

 least equal to that of the third of the whole organ ; the second is almost as 

 long as the third, and has the form of a reversed cone. The labrum of the 

 neuters is large, corneous, and falls perpendicularly under the mandibles. 



These Hymenoptera compose the genus 



FORMICA, Linnaeus, 



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 domiciles 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 recognised. Their 

 antennae are geniculate, and usually somewhat largest near the extremity ; 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 maxillse and labium are small; the palpi are filiform , 

 and those of the maxilla? the longest ; the thorax is compressed laterally, and 

 the almost ovoidal abdomen furnished, in the females and neuters, sometimes 

 with a sting, and sometimes with glands that secrete a particular acid called 

 formic. 



They form communities which are frequently extremely numerous. Each 

 species consists of three kinds of individuals: males and females which are fur- 

 nished with long wings, less veined than those of the other Hymenoptera 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 domicile in transitu. They leave it the moment their wings are 

 developed. The females wander to a distance from their birthplace, 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 domicile, tear off their wings, pre- 

 vent 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 establish it in the ground; in 



