Miscellaneous. 151 
When we examine with the naked eye or with a lens the embryos 
of the brown Aphis of the maple at the moment of their being pro- 
duced by the females, or after opening the bodies of the latter, we 
see at once that all of them have not the same coloration. In some 
they are of a tolerably bright green, whilst in others their colour is 
more or less brownish or greenish brown. The brown embryos pre- 
sent no peculiarities, and only differ from their mothers by characters 
analogous to those which are remarked in all species of Aphides 
between the newly born young individuals and the adult females. 
As in these latter, their bodies and appendages are furnished with 
rather long simple hairs, and, like all young Aphides at the moment 
of their birth, they already contain rudiments of embryos in the 
interior of their generative apparatus. If, on the other hand, we 
examine the green embryos, we at once detect, besides their peculiar 
coloration, very marked differences between them and their brown 
congeners. The various parts of the body and limbs do not present 
the same conformation as in the latter, but one is especially struck 
by the extraordinary development and the unusual appearance of 
their tegumentary system. Thus their surface is no longer furnished 
only with simple hairs, but also and priucipally with scaly transpa- 
rent lamella, more or less rounded or oblong, and traversed by 
divergent and ramified nervures. These lamellz occupy especially 
the anterior margin of the head, the first joint of the antennze (which 
is very stout and protuberant), the outer edge of the tibize of the two 
anterior pairs of legs, and the lateral and posterior margins of the 
abdomen. Moreover the whole dorsal surface of the latter and of 
the last thoracic segment is covered with a design having the aspect 
of a mosaic composed of hexagonal compartments, and which is 
not without analogy to the pattern formed by the scaly-plates of 
the carapace of tortoises. These peculiarities give our insect a great 
elegance of appearance, which causes it to be much in request with 
the amateurs of the microscope in England, where it is commonly 
known under the name of the “leaf-insect.’’ The entire animal is 
strongly flattened, and resembles a small scale applied to the surface 
of the leaf upon which it reposes, and on which it requires a certain 
amount of care to detect it. 
Another remarkable character of these abnormal individuals of 
Aphis aceris is the rudimentary state of their generative apparatus. 
This is reduced to a few groups of small pale and scarcely visible 
cells, none of which arrives at maturity to become transformed into 
an embryo; and it retains this character as long as it is possible to 
observe the animal. The functions of nutrition, also, are performed 
in them in a very unenergetic manner ; for from the moment of their 
birth until that at which we cease to observe them, they increase 
but little in size, attaining scarcely 1 millimetre. They undergo no 
change of skin, never acquire wings like the reproductive individuals, 
and their antennze always retain the five joints which they present - 
in all young Aphides before the first moult. Nevertheless they 
possess a well-developed rostrum and an intestinal canal, the peri- 
