HOP-FLY. 
69 
Early in the year these bhghts are scattered along the 
stems, but as soon as the little ones come to light, and 
any of the females yet deposited ova. The rose tree was placed in the window 
of an apartment in which there was no fire, and where the temperature ranged 
from about 45" Fahr. to 50" Fahr. In the second week of November, as the 
temperature of the season became cooler, I first noticed several specimens with 
rudiments of wings, and a few days afterwards these cast their skins and be- 
came fully developed. Most of these individuals were males. At this time 
there were also a great many very young specimens. On the 30th of Novem- 
ber the number of winged individuals had greatly increased ; there were many 
Avith only the rudiments of wings : and there was also a great abundance of 
black oval eggs distributed everywhere on the young shoots of the plant, not 
only on the leaf-buds, but on the stems of the leaves and branches. I saw an 
Aphis at that moment bearing two eggs at the extremity of her body. On 
placing one of these beneath the microscope, I was quickly assured of its real 
nature: it was not a capsule that included a ready-formed embryo, but a true 
egg. When first deposited the egg is of an orange-yellow colour, but it soon 
acquires a much darker hue, and ultimately becomes of a deep, shining black. 
The colour is entirely dependant on the pigment of the shell, and is much 
darker in some specimens than in others. The eggs are firmly glued to the 
plant, and are not easily removed. The egg of the Aphis is similar to that of 
other insects ; it is composed of an orange-colored yelk, formed of yellow, nu- 
cleated cells, and surrounded by a very slight quantity of transparent vitelline 
fluid. It contains also a very large germinal vesicle, with a distinct ynacula. 
or nucleus. This vesicle is three or four times as large as the cells that compose 
the yelk, and, unlike that of most other impregnated eggs of insects, does not 
disappear until some time after the egg is deposited. The vesicle is so persis- 
tent, that in one instance in which I examined an egg, shortly after it came 
from the body of the Aphis, it did not disappear for several seconds after the 
egg was crushed under the microscope. 
" Wishing to observe the deposition of more eggs, I selected four speci- 
mens of the Aphis for experiment : two of these were males, which as yet were 
in the pupa state, and had only the rudiments of wings ; the other two were 
large apterous females : these were placed on a detached branch of the rose, in- 
closed in a stoppered glass vessel, and removed to an apartment in which the 
temperature ranged from 55" Fahr. to about 60" Fahr. On the 2nd of Decem- 
ber, when the temperature of the room was 58" Fahr., I was surprised to find 
that these specimens were again producing living young. One of the large ap- 
terous females had already produced its living oflfspring, and the other was at 
that very moment in the act of parturition. The posterior part of the body of 
