148 NATURAL ARRANGEMENT OF INSECTS. 



•when all subsequent naturalists have wondered at the 

 beauty of the analogy, we may well be struck with 

 admiration at finding this relation confirmed by those 

 definite principles of the law of representation which 

 we advocate. If the circular group which includes the 

 Aphides be compared with all those which comprehend 

 their prototype here mentioned, all these parallel rela- 

 tions will come out. 



(138.) The Coccides, or plant bugs, succeed the last 

 tribe : these are also of a very small size, and in their 

 ordinary appearance resemble a scale ; all the parts of 

 the body being concealed underneath. They live on the 

 bark and leaves of vegetables, whose juices they suck ; 

 and are great pests to our hothouse and greenhouse 

 plants. The males have wings, and are much smaller 

 than the females, which are apterous. The Coccus 

 Adonidum Linn, is a familiar example of this family: its 

 shape has been aptly compared to that of an Oniscus, 

 or wood-louse : the whole insect is of a pale rose colour, 

 and appears more or less covered with a fine white meal 

 or powder: the male is very small, likewise rose-coloured, 

 somewhatmealy, with semi-transparent milk-white wings, 

 and four long filaments at the tail : the young are 

 hatched under the husk or body of the parent, and 

 afterwards disperse to feed separately. In regard to 

 their technical characters, the Cocci have many peculiar 

 to themselves. The female alone is furnished with a 

 rostrum, or sucker, while the male has only two- large 

 membranaceous wings : this circumstance would seem to 

 throw a suspicion on the propriety of placing these in- 

 sects in an order where the number of wings are inva- 

 riably four ; more particularly, as Latreille remarks 

 that the Coccus Ulmi has two poisers. But the whole 

 characters, and more especially the innumerable analo- 

 gies of these insects, show they are the most aberrant of 

 Hemiptera, and therefore contain such insects as are 

 most defective in the powers of flight, just as are the 

 Coleoptera in the circle of the Ptilota; while their ana- 

 logy to the CassidcB, Oniscus, and other chelonian types. 



