Dr. Burnett on the Development of Viviparous Aphides. 63 
and carefully repeated ; and there can now be no doubt that the 
virgin Aphis reproduces her kind—a phenomenon which may be 
continued almost indefinitely, ending finally in the appearance of 
individuals of distinct male and female sex, which lay the founda- 
tion of new colonies in the manner just described.* 
The question arises, what interpretation is to be put upon these 
almost anomalous phenomena? Many explanations have been of- 
fered by various naturalists and physiologists, but most of them 
have been as unsatisfactory as they have been forced, and were 
admissible only by the acceptance in physiology of quite new 
features. 
As the criticism I intend to offer upon some of these opinions, 
will be the better understood after the detail of my own researches, 
I will reserve their future notice until the concluding part of this 
Aphis with which I am acquainted, the Aphis Carye of Har- 
ris.~ While in Georgia, this last spring, it was my good fortune 
that myriads of these destroyers appeared on a hickory which 
grew near the house in which I lived. The number of broods on 
this tree did not exceed three, for with the third series their num- 
bers were so great that their source of subsistence failed and they 
gradually disappeared from starvation. The individuals of each 
tood were, throughout, of the producing kind, no males having 
been found upon the closest search; they were all, moreover, 
winged ; and those few which were seen without these appenda- 
Ses appeared to have Jost them by accident. I mention this fact 
especially, since it has been supposed by naturalists that the fe- 
males were always wingless, and therefore that the winged indi- 
Viduals, or the males, appeared only in the autumn.: 
he first brood, upon their appearance from their winter hiding- 
Places, were of mature size, and I found in them the developing 
germs of the second brood quite far advanced. On this account 
it was the embryology of the third series or brood alone, that I 
Was able to trace in these observations. 
* For details of experiments by which Bonnet’s original results were verified, see 
Réaumur, Mémoires, iii, Mém. 9 and 11, and vi, Mém. 13. Also, 
egeer, Mémoires, iii, ch. 2, 3. 
Curtis, Trans. Linn. Soc, vi. Philos. Trans. 1771. 
D vages, Journ. de Physique, i. ; 
Falta Mémoires, ii, p. 442. See also the more modern writers, and especially 
irby and Spence, Introduction to Entomology, iv. p. 161. ees 
to V arris, A treatise on some of the Insects of New England which are injurious 
of We etion- 2nd ed. 1852. p. 208, As Dr. Harris says, it is probably Lachnus 
Illiger, (Cinara of Curtis, 
F) ot Sane eens pts uction to the modern Classification of Insects, &c, Lon- 
Gin - i, p. 488—but especiall 
“» Parthenogenesis, éc., 28, ae and p. 59, note, where he says, “ Many of the 
virgin viviparous Aphides acquire wings, but never perfect the generative organs!” 
