I.] METAMORPHOSES OF INSECTS. 19 



cockroaches, &c.), Euplexoptera (earwigs), and Thy- 

 sanoptera, a small group of insects well known to 

 gardeners under the name of Thrips (PL I. and II., 

 Figs. I and 2) the larvae when they quit the egg 

 already much resemble the mature form, differing, in 

 fact, principally in the absence of wings, w r hich are 

 more or less gradually acquired, as the insect in- 

 creases in size. They are active throughout life. 

 Those specimens which have rudimentary wings are, 

 however, usually called pupae. 



The Neuroptera present, perhaps, more differences 

 in the character of their metamorphoses than any 

 other order of insects. Their larvae are generally 

 active, hexapod little creatures, and do not vary 

 from one another in appearance so much, for in- 

 stance, as those of the Coleoptera, but their pupae 

 differ essentially ; some groups, namely, the Psocidae, 

 Termitidae, Libellulidae, Ephemeridae, and Perlidae, 

 remaining active throughout life, like the Orthoptera ; 

 while a second division, including the Myrmeleonidae, 

 Hemerobiidae, Sialidse, Panorpidae, Raphidiidse, and 

 Mantispidae, have quiescent pupae, which, however, in 

 some cases, acquire more or less power of locomotion 

 shortly before they assume the mature state ; thus 

 that of Raphidia, though motionless at first, at length 

 acquires strength enough to walk, even while still 

 enclosed in the pupa skin, which is very thin. 1 



One of the most remarkable families belonging 

 to this order is that of the Termites, or white ants. 

 They abound in the tropics, where they are a perfect 

 pest, and a serious impediment to human develop- 

 ment. Their colonies are extremely numerous, and 



1 Westwood's Introduction, vol. ii. p. 52. 



C 2 



