6 INTKODUCTION. 



the use of its legs ; as it grows larger it is soon obliged to 

 cast off its skin, and, after one or two moultings, its body- 

 not only increases in size, but becomes proportionally longer 

 than before, while little stump-like wings begin to make their 

 appearance on the top of the back. After this, the grass- 

 hopper continues to eat voraciously, grows larger and larger, 

 and hops about without any aid from its short and motion- 

 less wings, repeatedly casts off its outgrown skin, appearing 

 each time with still longer wings, and more perfectly formed 

 limbs, till at length it ceases to grow, and, shedding its skin 

 for the last time, it comes forth a perfectly formed and ma- 

 ture grasshopper, with the power of spreading its ample 

 wings, and of using them in flight. 



Hence there are three periods in the life of an insect, more 

 or less distinctly marked by corresponding changes in the 

 form, powers, and habits. In the first, or period of infancy, 

 an insect is technically called a larva, a word signifying a 

 mask, because therein its future form is more or less masked 

 or concealed. This name is not only applied to grubs, cat- 

 erpillars, and maggots, and to other insects that undergo a 

 complete transformation, but also to young and wingless 

 grasshoppers, and bugs, and indeed to all young insects be- 

 fore the wings begin to appear. In this first period, which 

 is generally much the longest, insects are always wingless, 

 pass most of their time in eating, grow rapidly, and usually 

 cast off their skins repeatedly. 



The second period — wherein those insects that undergo a 

 partial transformation retain their activity and their appe- 

 tites for food, continue to grow, and acquire the rudiments 

 of wings, while others, at this age, entirely lose their larva 

 form, take no food, and remain at rest in a deathlike sleep — 

 is called the pupa state, from a slight resemblance that some 

 of the latter present to an infant trussed in bandages, as was 

 the fashion among the Romans. The pupae from caterpillars, 

 however, are more commonly called chiysalids, because some 

 of them, as the name implies, are gilt or adorned with golden 



