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spots. When irritated, this caterpillar has the power 

 of projecting from the fore-part of its body a pair of 

 orange-colored feelers, which exhale an intolerably 

 nauseous odor, and, like those of the snail, can be 

 withdrawn and concealed at pleasure. This scent- 

 organ is given to it for repelling its enemies, and it 

 has, undoubtedly, made the insect known to many 

 of you. Like the caterpillar of the turnip, this retires 

 from the plants when fully grown, suspends itself in 

 the same way, and, in process of time, becomes a but- 

 terfly. The only means that occur to me for destroy- 

 ing this insect, consist in carefully picking it, in the 

 caterpillar state, from the plants which it inhabits. It 

 is evident, however, that this can be done only to a 

 limited extent ; and, fortunately, it can be necessary 

 only with respect to the parsley, for the abundant 

 foliage of the other plants renders them less hable to 

 suffer by the loss of a portion of it. 



The lettuce and cabbage, in common with almost 

 every plant, are subject to the attack of their pecuhar 

 aphides, or plant-lice. The fecundity of these insects 

 surpasses that of any known animal ; for Reaumur has 

 proved, that, in five generations, one individual may 

 become the progenitor of nearly six billions of descend- 

 ants ; and many generations succeed each other in a 

 single season. What is still more singular in regard 

 to these insects, is their mode of increase. The first 

 brood is hatched in the spring from eggs laid in the 

 preceding autumn, but all the other broods during 

 summer are produced ahve.* Aphides, in all their 



* For some other particulars a paper, by the author, may be consulted 

 in "The New England Farmer," Vol. VI. p. 393. 



