i] METAMORPHOSES OF INSECTS. 25 



the perfect insect principally in the absence of wings, 

 which are gradually acquired. In their metamor- 

 phoses they resemble the Orthoptera, and are active 

 through life. The majority are dull in colour, though 

 some few are very beautiful. The species constituting 

 this group, though very numerous, are generally small, 

 and not so familiarly known to us as those of the 

 other large orders, with indeed one exception, the 

 well-known Bug. This is not, apparently, an indi- 

 genous insect, but seems to have been introduced. 

 The word is indeed used by old writers, but either 

 as meaning a bugbear, or in a general sense, and not 

 with reference to this particular insect. In this country 

 it never acquires wings, but is stated to do so some- 

 times in warmer climates. The Heteroptera cannot 

 exactly be said either to sting or bite. The jaws, of 

 which, as usual among insects, there are two pairs, 

 are like needles, which are driven into the flesh, and 

 the blood is then sucked up the lower lip, which has 

 the form of a tube. This peculiar structure of the 

 mouth prevails throughout the whole order ; conse- 

 quently their nutriment consists almost entirely of 

 the juices of animals or plants. The Homoptera 

 agree with the Heteroptera in the structure of the 

 mouth, and in the metamorphoses. They differ prin- 

 cipally in the front wings, which in Homoptera are 

 membranous throughout, while in the Heteroptera, 

 the front part is thickened and leathery. As in the 

 Heteroptera, however, so also in the Homoptera, 

 some species do not acquire wings. The Cicada, 

 celebrated for its chirp, and the lanthorn fly, belong 

 to this group. So also does the so-called Cuckoo-spit, 

 so common in our gardens, which has the curious 



