114- NATURAL ARRANGEMENT OF INSECTS. 



adult state.* The analogies, therefore, of these two 

 orders are not only placed beyond all doubt, but find 

 their corresponding representatives in vertebrate as 

 well as annulose animals. The Aphides, or plant lice, 

 are the bees of the Hemiptera ; for these two groups 

 contain the only insects which secrete honey. This 

 resemblance, however, is not a mere analogy, but an 

 affinity. Latreille, without any scruple, places Thrips 

 in the same division as Aphis, 'from which, however, it 

 differs so remarkably as to possess jaws j and he alludes 

 to a fact, what every one may verify, viz. that when 

 these insects (Thrips) are irritated, they turn up their 

 body in the manner of the Staphylini. The resemblance 

 which the onisciform shape, and often the coriaceous 

 covering, of the Coccides bears to Coleoptera, exactly 

 accords with every thing we have said on the analogies 

 of the latter group. They have the hardest covering 

 of all insects ; just as the armadillos among quadrupeds, 

 and the chelonians, or tortoises, among reptiles. Pur- 

 suing the especial analogy apparent in our table, we 

 find, also, that the Coccides and the Coleoptera are the 

 most imperfect flyers in their own groups : the females 

 of the former are apterous ; while the wings of the 

 males are only two, and these fold over each other, 

 horizontally, on the body. The reader will remember 

 what we have said on the wings of the Coleoptera, which, 

 in effect, are but two-winged insects ; the upper pair, 

 or elytra, being almost useless as organs of flight. 

 With such striking and even beautiful representations 

 of four out of the five orders of the Ptilota, as this 

 table substantiates, we may very well leave the last for 

 future investigation. The truth is, that, until the ab- 

 errant tribes of the Hemiptera, and perhaps even those 

 which are typical, are properly analysed, it will be 

 manifestly impossible to determine what other insects 

 enter into that group where at present we place only 

 Aleyrodes. We should not be surprised, however, if 



* The raptorial feet of the larva? of the cicadas may possibly be used to 

 dress out the juices of leaves, &c. 



