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The term larva, originally signifying a mask, is ap- 

 plied to all insects in the young or growing state ; to 

 caterpillars, grubs, and maggots, whose future forms 

 are completely disguised, and to the young of bugs, 

 crickets, grasshoppers, plant-lice, and some other in- 

 sects, whose subsequent stages are unattended with 

 any remarkable changes of form. The second state 

 is the pupa ; and, while in this, the insects last men- 

 tioned continue to feed, grow, and move about like the 

 larvae, which they also resemble in form. The third 

 or final change developes all in their perfect state, with 

 new organs and propensities. Hence two kinds of 

 transformation are recognised. One of them seems to 

 consist in little more than a casting of the external 

 skin, and the acquisition of additional organs, with a 

 preservation of the same general form and habits ; this 

 is called incomplete transformation : the other, including 

 an eating, a quiescent, and a winged state, exhibits 

 insects, in their progress, in three distinct forms, and 

 three different modes of existence ; this constitutes a 

 complete transformation. 



A few examples will illustrate the transformations, 

 or metamorphoses, of some common insects, and pre-- 

 sent a general view of their history. The squash-bug * 

 passes through an imperfect transformation. In shape 

 it is, while young or a larva, proportionally shorter and 

 more rounded than the perfect insect, and its color is 

 of a pale, ashy hue. When it enters upon the pupa 

 state its form lengthens, and two little scales are seen 

 upon its back, which are sheaths representing and 



* Cortus ordinatus. Say. 



