APHIS. Ml 



which young, if also kept apart, will likewise 

 produce, and so on, without the presence of a 

 male. Towards autumn, however, this singular 

 fructification begins to lose its wonderful effects. 

 The Aphides cease to bring forth females only ; 

 males likewise are produced, who immediately 

 celebrate that nuptial rite which is to commu- 

 nicate fertility to the whole female posterity of 

 the following summer. These facts are un- 

 questionable ; and the experiments are easily 

 made. Let a person, in summer, take the leaf 

 of a cabbage, which is infected with these mi- 

 nute insects, and he will find on the under sur- 

 face a number of them together, covered with 

 a sort of powder or whitish down. Upon care- 

 fully observing one of the largest, he will not 

 fail, in a short time, to detect it in the act of 

 parturition, when the young may be separated 

 and kept apart on fresh cabbage leaves. — Most 

 plants have their peculiar Aphides, but some 

 are found on several plants. The species are 

 with difficulty distinguished, and with still more 

 difficulty defined. Linnaeus has described but 



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