SUCKING INSECTS. 181 



sensibly agitated by the air. Upon examining this 

 substance, we find that it conceals a multitude of 

 small wingless creatures, which are busily employed 

 in preying upon the limb of the tree beneath. This 

 they are well enabled to do, by means of a beak 

 terminating in a line bristle, which, being insinuated 

 through the bark and the sappy part of the wood, 

 enables the creature to extract, as with a syringe, the 

 sweet, vital liquor that circulates in the plant. The 

 sap-wood {Mburnum) being thus wounded, rises up 

 in excrescences and nodes all over the branch, and 

 deforms it ; the limb, deprived of its nutriment, grows 

 sickly ; the leaves turn yellow, and the part perishes. 

 Branch after branch is thus assailed, until they all 

 become leafless, and the tree dies. 



' Aphides attack the young and softer parts of 

 plants ; but this insect seems easily to wound the 

 harder bark of the apple, and by no means makes 

 choice of the most tender parts of the branch. They 

 give a preference to certain sorts, but not always the 

 most rich fruits ; as cider apples and wildings are 

 greatly infested by them, and, from some unknown 

 cause, other varieties seem to be exempted from their 

 depredations. The Wheeler's- russet and Crofton- 

 pippin I have never observed injured by them. This 

 insect is viviparous, or produces its young alive,* 

 forming a cradle for them by discharging from the 

 extremities of its body a quantity of long, cottony 

 matter, which, becoming interwoven and entangled, 

 prevents the young from falling to the earth, and 

 completely envelops the parent and the offspring. 

 In this cottony substance, we observe, as soon as the 

 creature becomes animated in spring, and as long as 

 it remains in vigour, many round pellucid bodies, 

 which, at first sight, look like eggs, only that they are 

 larger than we might suppose to be ejected by the 



* See Insect Transformations, p. 112. 

 VOL. XII. 16 



