182 NATURAL HISTORY. [CH, X. 



" Aphides in general 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 nxakes 

 choice of the most tender part 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 to be injured by them. 

 This insect is viviparous, or produces its young alive, 

 forming 1 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 envelopes the parent and offspring. In 

 this cottony substance we observe, as soon as the 

 creature becomes animated in the spring, and as 

 long as it remains in vigour, many round pellucid 

 bodies, which, at the first sight, look like eggs, only 

 that they are larger than we might suppose to be 

 ejected by the animal. They consist of a sweet, 

 glutinous fluid, and are probably the discharges of the 

 aphis, and the first food of its young. That it thus 

 consumed I conjecture from its diminution, and its 

 by no means increasing so fast as faecal matter would 

 do, from such perpetually feeding creatures. I have 

 not, in any instance, observed the young to proceed 

 from these globular bodies, though they are found of 

 various ages at all times during the season. This 

 lanuginous vestiture seems to serve likewise as a 

 vehicle for dispersing the animal ; for though most 

 of our species of aphis are furnished with wings, I 

 have never seen any individual of this American 

 blight so provided, but the winds wafting about small 

 tufts of this downy matter, convey the creature with 

 it from tree to tree throughout the whole orchard. 

 In the autumn, when this substance is generally long, 

 the winds and rains of the season effectually disperse 



