50 INSECTA. 
Sometimes the elytra and wings, oval or triangular, and 
without a fringe of hairs along the margin, are inclined or 
tectiform., The rostrum is very distinct. The tarsi are ter- 
minated by two hooks, and the antenne have but six or seven 
joints. Such is the genus 
Apuis, Lin. 
Which we divide in the following manner. 
APHIs, 
Properly so called, where the antennz are longer than the thorax 
and consist of seven joints, the third of which is elongated; the eyes 
are entire, and there are two horns or mammillz at the posterior ex- 
tremity of the abdomen. 
Almost al! of them live in society on trees and plants, of which 
they suck the juices with their trunk. The two horns observed at 
the posterior extremity of the abdomen in a great number of species 
are hollow tubes from which little globules of a transparent, honey- 
like fluid frequently exude, on which the Ant eagerly feeds. 
In each community, during the spring and summer, we find 
Aphides that are always apterous, and semi-nymphs whose wings are 
yet to be developed; all these individuals are females, which produce 
living young ones that issue backwards from the venter of their 
mother, without previous copulation. The males, some of which are 
winged, and others apterous, only appear towards the end of sum- 
meror in autumn. They fecundify the last generation produced by 
the preceding individuals, which consists of unimpregnated apterous 
females. After coition the latter lay their eggs on branches of trees, 
where they remain during the winter, and from which, in the spring, 
proceed little Aphides, which soon multiply without the assistance 
of the males. ; 
The influence of a first fecundation is also extended to seven suc- 
cessive generations. Bonnet, to whom we are indebted for most of 
these facts, by isolating the females, obtained nine generations in the 
space of three months. 
The wounds inflicted on the leaves or tender twigs of plants, by 
Aphides, cause those parts of the vegetable to assume a variety of 
forms, as may be observed on the shoots of the Lime tree, the leaves 
of Gooseberry bushes, Apple trees, and particularly those of the 
Elm, Poplar, Pistachio, in which they produce vesicles or excres- 
