SEX IN APHIS. 
87 
buzz before it takes wing from a flat surface. The 
action is curious, and produces a considerable hum- 
ming noise when the flies escape numerously from their 
cones. Shortly after the females have alighted they 
commence giving birth to living young. In Ghaito- 
plioms aceris these young form large patches, arranged 
concentrically to the abdomen of the mother. They 
may number fifty or more, and scarcely differ in size 
one from the other. 
The winged females appear to be more tenacious of 
life than the apterous. I have received them alive 
both from Pembroke and Kewcastle, having travelled 
thence by post inclosed in goosequills. This is by far 
the best method of transporting them, as the porous 
character of of the quill prevents their being drowned 
in their own watery perspiration. 
SEX IN APHIS. 
Several early observers have erroneously stated that 
the female Aphis is at different periods of her life both 
viviparous and oviparous. The acuteness of Newport 
failed him when he concluded ®‘that Aphides,’^ mean- 
ing the same individual Aphides, deposit at one time 
true ova and at others produce living young.” He 
does not tell us on what grounds he decided that the 
two pupae of Ajphis rosce which he confined for experi- 
ment with two oviparous females were males. The 
subsequent appearance of both ova and living young 
can easily be explained if any mistakes were made 
between the winged viviparous female and the winged 
male. In reality the sex of the latter could only have 
been decided on with certainty by dissection, to which 
he does not appear to have resorted. It may be pretty 
certainly asserted that the viviparous Aphis is never 
^ G, Newport, “ On the Generation of Aphides,” ‘ Linn, Trans. 
vol. XX, xr 281. 
