544 INSECTS AT nOME. 



which time uot a male Aphis had been suffered even to ap« 

 proach them. 



It is in consequence of this remarkable mode of production 

 that the twigs and buds become so rapidly covered with 

 Aphides, the quickly-succeeding generations crawling over the 

 backs of their predecessors, so as to arrive at an unoccupied spot 

 of bark in which they can drive their beaks. Thus, at the be- 

 ginning of a week, say on Monday, a rose-tree may be apparently 

 free from Aphides, or have at the most six or seven of the 

 ' blight ' upon it. But, by Thursday, the whole plant will be 

 so thickly covered with Aphides that scarcely a particle of the 

 bark can be seen, the whole being crowded with the green 

 bodies of the insect, each with its beak dug deeply into the 

 plant, and draining it of its juices. It is difficult to prescribe 

 any mode of getting rid of these garden pests. The double-brusli 

 answers as well as anything I know that can be applied by the 

 hand of man ; but there is nothing so effective as the natural 

 foes of the Aphides, namely the Lady-birds, whose mode of feed- 

 ing has already been described, and the Syrphi or Hawk-flies. 



If the reader will refer to the illustration on Woodcut 

 LXII., he will see that from the back of the Aphis and to- 

 wards the tail there are two slender projections. These are 

 tubes, from which exudes a sweet liquid ; which, with the aid 

 of the microscope, can be seen starting in minute drops from 

 the end of each tube. When the Aphides are in great pro- 

 fusion upon a tree, this liquid falls from them, and covers the 

 leaves with the sweet, sticky substance which is so familiar to 

 us under the name of ' houej^-dew.' Trees thus distinguished are 

 always overrun by swarms of ants, which lick the sweet drop- 

 pings from the leaves and hold high revels on this substance, 

 whose origin was once so mysterious. 



The ants even go fartlier than this. Not content witli 

 taking the honey-dew that has fallen from the Aphides, they 

 anticipate its fall, and eagerly lap up the sweet secretion as it 

 exudes from the insects. In fact, they make much the same 

 use of Aphides as we do of cows, and even carry off the ant- 

 cows, as they may be called, to their own nests, and there keep 

 them. That the ants do this has long been known, but the 

 notion of keeping milch-cows seemed so far beyond the cajDaci- 

 ties of an insect that many persons refused to give credence 



