APPLE-BLIGHT. 77 



union. They are continually seen in company, and a little 

 further scrutiny presently discovers that the Ants are the 

 followers of the Aphides, and entirely for what they can get 

 out of them. Last August, the stalks of an elder shrub in 

 our garden were absolutely blackened at the joints by Elder 

 Aphides, and among these were continually to be seen a multi- 

 tude of brown Ants, demanding and receiving their supplies of 

 honey-dew as emitted by the former. 



Besides the general analogy which exists between flocks of 

 Aphides and flocks of sheep, in their gentle nature, their gre- 

 garious habits, and in their being appropriated so extensively 

 for food, there may be noticed, in several instances, a curious 

 kind of external rapport between "them and the woolly-coated 

 quadrupeds. 



There are some species of Aphides which are actually clothed 

 with a sort of wool or down. One of them, a four-winged 

 Gall insect, 1 is found in June or July on the poplar, or may 

 be often noticed at that season, flying or floating about in the 

 air, like a small white tuft of down. Another hoary-coated 

 Aphis is unfortunately too well known to apple-growers under 

 the name of " White Blight." The branches of those trees 

 selected for their pasture by our insect sheep are soon invested 

 by their numerous fleeces with a hoary aspect, appearing in 

 spring and increasing through the summer. These fleeces are 

 found upon examination to consist of a woolly or cottony sub- 

 stance, exuded from the insects' bodies, and under its cover a 

 multitude of these wingless Aphides are incessantly at work 

 with their destructive pipes, sucking up the sweet vital juices of 

 the tree : the old and the young being thus employed together, 

 parents with their offspring, to whom this soft down serves the 

 purpose of a cradle. 



There is a peculiarity which distinguishes the Aphis from 

 perhaps every other creature in the animal world, a physical 



1 Eriosoma populi. 



