HOMOPTERA. — APHID 439 
Pruni), at least in those individuals which ultimately acquire wings ; 
but the family is very anomalous in this respect, many specimens 
(indeed the majority) never acquiring wings (in which case the pupa 
is not to be distinguished from the mature larva or imago states), 
although at certain seasons of the year other individuals of the same 
species, and of both sexes, obtain fully developed wings.* It is also 
to be observed, that it is chiefly the females which are produced in 
this imperfect condition (fig. 117. 14. Aphis Rose ? ); and when 
we consider that these individuals are placed in the midst of an ample 
supply of food both for themselves and their numerous progeny, we 
cannot be surprised at the non-production of organs which would be 
comparatively useless ; whilst, at the same time, it is not unworthy of 
remark, that the loss of these organs is accompanied by an extraor- 
dinary development of the ovaries: moreover, the suddenness of the 
maturity of these apterous specimens, dependent upon the object of 
their production, namely, the checking of vegetation, at such time in 
the most luxuriant state, seems sufficient to account for the non-pro- 
duction of wings, which would require a greater period of time for 
their development. The species reside in great societies upon almost 
every species of plant, of which they suck the juices of the young 
shoots, leaves, stems, and even roots +, by the assistance of their 
proboscis, producing in many instances disease in the plant either by 
greatly weakening it, or by distorting young shoots and leaves ; some 
species raising vesicles, or other gall-like excrescences, in which whole 
generations of Aphides are residents. The anal tubercles above-men- 
tioned (which are wanting in some species), secrete a saccharine 
fluid of which ants are very fond; and it is this fluid dropped upon 
the adjacent leaves, or the extravasated sap flowing from the wounds 
* We have already seen in the Orthoptera and Fulgoride, that analogous in- 
stances occur, in which, however, rudiments of wings (quite unlike those of the true 
pupa) are acquired by some specimens, whilst others of the same species have them 
of full size ; with the example of the Aphides in view, we can but be surprised that 
there should be entomologists who doubt the specific and even the generic identity 
of such individuals. See further observations hereon under Hydrometride. 
+ A writer in the Entomol. Magazine, No. 14. p. 337., states that he found whole 
troops of Aphides in the pips of large sound codling apples! The same writer has 
published ample details of the injuries committed by Aphis Humuli upon the crops 
of hops in the same work (No. 3. p. 217.), in which (No. 3. p. 315.) another 
observer has stated that he has observed the hop-fly produce young actually provided 
with wings ! 
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