- HEMIPTERA. 123 
by his experiments on the reproduction of plant-lice. This 
naturalist, whose name will live quite as long as those ot 
Réaumur and of Trembley, was Charles Bonnet, of Geneva. 
Charles Bonnet made the extraordinary discovery that aphides 
can increase and multiply without copulation. An isolated’ speci- 
men can produce a series of generations of its kind. We will 
relate the curious experiments of the Genevese naturalist. He 
placed: in a flower-pot, filled with mould, a phial full of water, and 
put into this phial a little branch of spindle, having only five or 
six leaves, and perfectly free from any insect. On one of these 
leaves he placed a plant-louse, which was born under his own eyes, 
of a wingless mother. He then covered the branch with a glass 
shade, whose rim fitted exactly into the top of the flower-pot. 
Having taken these precautions, Charles Bonnet was perfectly cer- 
tain of being able to observe his prisoner at his ease. He could 
keep it under his eye and under his hand, with more certitude and 
security than was the mythological Danaé, shut up, by order of 
Acrisius, in a tower of bronze. 
“T took care,” says Charles Bonnet, “to keep a correct journal 
of the life of my insect. I noted down its least movements ; 
nothing it did seemed to me indifferent. Not only did I observe 
it every day from hour to hour, beginning generally at four or 
five o’clock in the morning, and only leaving off at about nine 
or ten at night; but I even looked many times in the same hour, 
and always with the magnifying glass, to render my observation 
more exact, and to learn the most secret actions of my little lonely 
one. But if this continual application cost me some trouble, and 
bored me not a little, im amends I had some cause for self-applause 
and for having subjected myself to all this trouble. . . . . My 
plant-louse changed its skin four times: on the 28rd, in the 
evening; on the 26th, at two in the afternoon; on the 29th, at 
seven o'clock in the morning; and on the 31st, at about seven 
o’clock in the evening. . . . . Happily delivered from these four 
illnesses through which it was obliged to pass, it at last reached 
that point to which, by my care, I had been trying to bring it. 
It had become a perfect plant-louse. On the 1st of June, at about 
seven o’clock in the evening, I saw, with great satisfaction that it 
had given birth to another; from that time I thought I ought to 
