APHIS. 
178 
leaf of considerable length, taken from a stove 
plant beset with Aphides of a dark lead-?blour, 
which were feeding on it in great numbers. On 
immersion they did not quit the stalk, but imme- 
diately their bodies assumed a kind of luminous 
appearance from the minute bubbles of air which 
issued from them. They were put under water at 
a quarter past six in the evening, and taken out 
at a quarter past ten the next morning, having 
continued immersed sixteen hours. On placing 
them in the sunshine some of them almost im- 
mediately shewed signs of life, and three out of 
four at least survived the immersion. One of the 
survivors, a male, very soon became wdnged, and 
another, a female, was delivered of a young one. 
Many years before this experiment, with a view 
to destroy the Aphides, which infested a plant in 
my green-house, I immersed one evening the 
whole plant, together with the pot in which it 
grew, in a tub of water. In the morning I took 
out the plant, expecting with certainty to find 
every Aphis dead ; but to my great surprize they 
soon appeared alive and well: and thus in addi- 
tion to the other extraordinary phenomena attend- 
ant on these insects, we find that they are capable 
of resisting the effects of immersion in water for 
a great length. When taken from the plant on 
which they feed and kept under water, they do 
not survive so long; their struggling in that case 
perhaps exhausts them sooner. This part of the 
subject might perhaps be pushed much farther: it 
is sufficient for our purpose to have shewn that 
JB 
