REPORT OP THE ENTOMOLOGIST. 35 



As before stated, ants are very fond of the sweet gummy substance 

 miscalled honey-dew, which is ejected from the anal tubes of plant-lice, 

 and it has been repeatedly stated on good authority that the ants cap- 

 ture the plant-lice, carry them to tlieir nests, and keep them there, like 

 milch-cows, for the sake of having a good supply of their favorite food 

 near at hand. Dr. Walsh states that ApMdes feeding on annual plants 

 hibernate in the imago or perfect-insect state. To show the iujury 

 done in England by these minute insects, Kirby and Speuco long ago 

 stated that their damage to hops alone made the difference of the duty 

 often as much as £200,000 (or in the neighborhood of $1,000,000) per 

 annum, more or less, in proportion as the fly prevailed or otherwise. 

 Happily, however, plant-lice are subject to a great many enemies which 

 materially diminish their numbers. Almost all the lady-birds {Coc- 

 cinellidce) feed upon them in both larva and perfect state. Minute hy- 

 menopterous insects, such as Axjhidius, &c., lay their eggs in the body of 

 the plant-louse, which, hatching into little grubs, eat out their interior 

 and thus destroy them. (See Hymenoiitera.) Several plant-bugs. Nobis 

 ferus, Phymata erosa, Beduvius 7'aptorius and multispinosus, pierce them 

 with their beak, and suck out their juices. (See Heteroptera.) Syrplius 

 and Leucopis, two-winged flies, also destroy them, (see Biptera ;) 

 Chrysopa, or the lace- wing fly, and Agrion, a dragon-fly, {see Neuropt&)'a,) 

 feed upon them, and many others, too numerous to mention here, all 

 join in this indiscriminate war upon the helpless but noxious i)lant- 

 lice. If any person interested in grape-culture will take a single leaf of 

 a grape-vine infested with plant-lice and observe it closely, ho will see 

 several individuals differing from the rest, being much swollen and of 

 a grayish-brown color, instead of the usual green, and each having a 

 round hole in the abdomen. This is done by a small hymenopterous or 

 four-winged fly, which deposits its eggs in the body of the doomed 

 plant-louse, which, hatchitig into a minute grub, devours the inside of 

 its victim, and after changing into a pupa inside the body of the aphis 

 and finally into the perfect fly, cuts its way out into the open air, and 

 emerges through this circular hole in the skin to lay the foundation of 

 new broods of aphis-destroying flies, leaving the empty hard gray skin 

 of its victim still clinging convulsively to the leaf. The number of these 

 empty skins with holes in them on some of the vine leaves will tes- 

 tify how much good this little insect does to the grapeculturist by de- 

 stroying his enemies. Aphides are likewise destroyed by other hymen- 

 optera, Passalcecus mandibular is, which stores them up in its cell or nest 

 as food for its young. Trypoxylon, Allotria, and many of the Ghalcididce 

 and other Hymenoptera are also benefactors by destroying multitudes of 

 these troublesome plant-lice. 



Aphis mali, apple plant-louse. The females deposit their eggs, which 

 are small, oval, and black, on twigs and bark in the No. 37. 



autumn; the insect is hatched out the next spring, [Magnified.] 

 and feeds upon the sap of the tree. The first broods 

 are all females, which in a short time, without any 

 intercourse with the males, give birth to living young 

 by the procees of gemmation, as before described. 

 These also produce other young ones, which are all 

 females as long as the summer lasts, and it is only 

 in the autumn that males are produced, which, 

 uniting with the females, become the parents of the eggs for the follow- 

 ing spring brood, thus bearing living young all the summer, and laying 

 eggs which can withstand the frosts of the winter in autumn for the 

 following spring seasonj whil'^ the parent: iusects in winter are d.Q^ 



