324 Miscellaneous. 
individuals, male and female, which copulate after moulting. This 
winged form is what I have called the Pseudogyne pupiféere. The 
fecundated female deposits, around the buds of the oak, brilliant 
black eggs without any covering. ‘These eggs hatch in the spring. 
Vacuna alni, according to authors (De Geer, Kaltenbach, Koch), 
appears in the spring in the form of a green founder Aphis, and 
produces young which acquire wings in June. 
I do not know these two forms, which are my Pseudogynes fonda- 
trices and émigranies ; but in July I have found, at Luchon, a large 
wingless Aphis of a brick-red colour, with a median line and four 
streaks (two on the shoulders and two at the nectaries) white, 
which deposited along the stems and under the leaves green young 
of two sizes. Although accustomed hitherto to apterous sexual 
forms, I immediately suspected that ‘this large red Aphis was the 
pupiferous form, although it was wingless. 
And, in fact, a very few days afterwards, and after a few very rapid 
moults, I saw the small individuals become active males, running 
about in search of the females and copulatimg with them. The 
Pseudogyne pupifere, which is wingless and red, is 1:10 millim. in 
length ; the green female is 1 millim. long, and its transparency 
shows a large egg in its abdomen. 
The male, which is also green, is 0°66 millim. in length. On 
pressing the abdomen very gently we see the penis issue, of the 
usual form of that of Aphidians. 
After copulation, a shining secretion of a pearly white is seen to 
make its appearance on both sides of the abdomen of the female ; 
this indicates that oviposition is about to take place. In fact, two 
or three days afterwards the egg is deposited, and the female in- 
dues it all round with the nacreous secretion that exudes from her 
abdomen, not in filaments, but in the form of small waxy plates. 
In tubes these eggs are placed upon the cork; I have not witnessed 
the oviposition in freedom. 
The discovery of the sexual forms of Vacuna alni completes the 
knowledge of these forms in all the known species of Aphidians 
which carry their wings horizontally. 
In Phylloxera and Aploneuwra the sexual individuals have no 
rostrum; nevertheless they enlarge and undergo at least one, and 
perhaps several moults. In the Vacune the sexual forms have a 
rostrum and feed. In this they approach the genus Schizoneura, 
several species of which have sexual forms bearing a rostrum. It 
is curious also to see in the genera Phylloxera and Vacuna species 
with a winged pupiferous form side by side with others with an 
apterous pupiferous form. 
But in any case nothing could be more dangerous than to attempt 
to judge by analogy of these singular animals. Seeing the two 
Vacune side by side, one would take them for the same insect: now 
one oviposits in August, and the other in December; one has the 
pupiferous form apterous, the other winged; one has no secretion, 
the other exudes nacreous plates. 
Consequently there still remain many observations to make before 
we can venture to undertake the classification of the Aphidians from 
a biological point of view.— Comptes Rendus, August 29, 1881, p. 425. 
