322 
OWEN’S POSITION IN 
which these animals produce with such wonderful 
fertility in summer, are all fatherless. So are the 
drones in a hive of bees. 
Among the aphides, this state of things, as a 
rule, persists throughout the summer ; and it is 
not until the autumn arrives, that the broods 
produced take on the characters of males and 
females, which die after their functions are per- 
formed and the eggs are laid. The eggs remain 
dormant during the winter ; and when they hatch, 
in spring, the aphides produced are sexless, 
though in some respects they resemble the true 
females. These sexless forms produce living 
broods, having the same characters as their pro- 
ducer ; and these give rise to others, in like manner, 
through the summer. It has been proved that this 
state of things may be maintained for three years, 
by keeping the insects warm and supplied with 
food ; indeed, there is no positive evidence that it 
need ever come to an end. 
The males and females are, in many respects, 
different from the sexless proliferators. Thus, 
to superficial observation, it appears as if the 
sexed ‘ generation,’ which may be called the form 
A, was succeeded by a certain number of sexless 
" generations ’ of the form B ; these by A, these 
by B again, and so on. In other words, the ‘ gene- 
rations ’ A and B alternate. 
In the course of the early decades of the nine- 
teenth century, the wide extension of exact investi- 
