EAPID INCREASE OE APHIDES. 
79 
The colour of the eggs of Aphides, added to their 
rarity, renders them often difficult to discover. During 
the months of February and March, when the leaf-buds 
of the rose begin to swell, the ova may be seen, like 
grains of gunpowder, fixed within their crevices of 
bark. The female attaches these eggs to some varieties 
only of Rosa canina and R. centifoUa, but occasionally 
she also affects some of our garden varieties. 
A single insect hatched from one of these shining 
black ova may be the mother of n^oiy billions of young, 
even during her lifetime. Latrielle says one female 
during the summer will prodiTce young at the rate of 
about 25 in a day ; and Eeaumur calculates that one 
Aphis may be the mother of the enormous number of 
5,904,900,000 individuals during the month or six 
weeks of her existence. Probably the daily birth as 
given by Latrielle is above the truth, yet I have wit- 
nessed the birth of eight young from the same mother 
in six hours, viz. from ten o’clock in the morning to 
four o’clock in the afternoon. However this may be, 
neither Tougard nor Morren is satisfied with Latrielle’ s 
billions, but both state that qumtillions are within the 
capabilities of a single mother’s efforts. Prof. Huxley 
makes a curious calculation, though for a different 
purpose, which at any rate affords some approximate 
idea of what a quintillion of Aphides might mean. 
Assuming that an Aphis weighs as little as yoVo ^ 
grain, and that it requires a man to be very stout to 
weigh more than two million grains, he shows that the 
tenth brood of Aphides alone, without adding the pro- 
ducts ‘of all the generations which precede the tenth, 
if all the members survive the perils to which ’they are 
exposed, contains more ponderable substance than five 
hundred millions of stout men ; that is, more than the 
whole population of China 
Facts like these regarding the prolific nature of 
Aphides afford sufficient explanation of the occurrence 
* Hnxley, “ On Organic Reproduction of ApRis,” ‘ Lin. Trans.,’ vol. 
xxii, p. 215. 
