26 DEFINITION OF THE TERM INSECT. 



I admit the validity of your objection, but by no arrange- 

 ment of insects in a simple series can we attain this object : 

 the difficulty, however, may perhaps be obviated in this 

 way. The distribution of organized matter, to adopt 

 Mr. Wm. MacLeay's metaphor a , begins in a dichotomy, 

 constituting the animal and vegetable branches of the 

 great tree of nature, and from these two great branches, by 

 means of infinite ramifications, the whole system is form- 

 ed, and, what is remarkable, these branches unite again 

 so as to represent a series returning into itself, a disco- 

 very due to the patient investigation and acumen of our 

 learned friend just mentioned. Now, in considering 

 the Aptera order, we find at first setting out from the 

 Hexapods, a dichotomy, where the Anqplura Leach 

 branch off on the one side, and the Thysanura Latr. on 

 the other — the former, by means of the Pediculidce, tak- 

 ing their food by suction, particularly Phthirus Leach, 

 or the Morpion (in which the segments of the trunk and 

 abdomen become indistinct 5 ) approach the Octopods by 

 the hexapod Ac art L. — the latter by Machilis polypoda 

 tending towards the Myriapods. In the Octopod branch 

 a further dichotomy takes place, from which you proceed 

 on one side to the Araneidce in the Arachnida, by Pha- 

 langium, &c. ; and in the other by Chelifer, &c. to Scorpio. 

 Again, the Myriapod branch also divides, going by the 

 Iulidce to one branch of the Isopod Crustacea, and by the 

 Scolopendrida to another. 



But there is another view of this subject before alluded 

 to, which may be repeated here, and which seems to 



a Hor. Entomolog. 134. 200. 



b Zoolog. Miscell, iii. t. 146. In this figure the segments are 

 made much more distinct than they are in my specimen. 



