FAMILY APHIDID^. ld§ 



not furnish wholesome nutriment to several dififerent species of insects. Indeed the same 

 plant may bear two or more kinds of lice, and they may occupy the root, leaf, stem, or 

 bud. 



I have alluded to the greatness of the number of aphides. Considerable attention has 

 been paid to this part of their natural history. Reaumijr has probably investigated the 

 mode and rate in which they increase, better than any other naturalist : he ascertained 

 that a single individual may be the progenitor of six thousand millions of individuals 

 during the life of five generations. The eggs are laid in the autumn upon the buds of the 

 plant, and are hatched in the spring : this takes place when the leaf is just expanding 

 and tender, to which the delicate aphis is attached by its sucker, and from which it sucks 

 the juice. They grow rapidly, and speedily come to maturity. The most remarkable fact 

 connected with this first brood, which is hatched from the egg, is, that the individuals, 

 however numerous, are all wingless females, which present this anomaly, that they are 

 competent, without intercourse with the male, to beget another generation of females, and 

 this another, and so on to the seventh generation. After these generations have succeeded 

 each other, another generation, consisting of males and females, is produced in the au- 

 tumn : pairing takes place, and the eggs are laid upon the buds as has been stated, and 

 in due time are hatched ; and thus the broods are produced in the successive seasons after 

 the same fashion. The generations all perish in the autumn, and the subsequent continua- 

 tion of the race is committed to the egg. The males have wings. 



A young leaf that curls, or looks unhealthy, is probably infested with aphides : they 

 will often be found clustered together, engaged in sucking the jviices of the leaf; and as 

 they are voracious feeders, nature has provided them with the means of ejecting their food 

 in an uncommon way. This is done through the two posterior tubes : the ejected matter 

 appears first in the form of a pellucid fluid, which is sweet, and has received the name of 

 honeydew. Ants, being fond of sweet fluids, are in the habit of frequenting plants infested 

 with aphides, which they treat in a very gentle and tender manner, feeding merely upon 

 the fluid without inflicting the slightest injury upon the insects that draw it from the 

 plant. Another insect, however, the lacevnng, unceremoniously thrusts its curved beak 

 into the sides of the aphis, and sucks the insect dry, leaving nothing but an empty skin. 

 The presence of ants upon a plant indicates also the presence of aphides. 



The aphis, as already stated, infests most plants : the rose, the asters, apple, peach, 

 pear, cabbage, etc. etc. are only a few among many upon which we may find it to an in- 

 jurious extent. Besides it is not unfrequently the case that they exist beneath the soil and 

 upon the roots, where they cluster together in vast numbers, and extract the ascending 

 nutriment : these are usually white. 



The peach-tree is known to suffer extremely from the aphis, which, when numerous, 

 aflects it in a way that prevents its bearing fruit. My own trees suffered for three succes- 



