CHARACTERS FROM CAUDAL APPENDAGES. 255 



merely ornaments to these elegant creatures, but 

 are actually used by them to scare and frighten 

 away their enemies. On this curious fact, hitherto 

 unrecorded, we shall subsequently enlarge ; yet this 

 analogy, being established, shows that the crested 

 and horned structures are synonymous ; and that, 

 under one modification or the other, it is as prevalent 

 among particular groups of birds, as of quadrupeds. 

 On turning to insects, it is no less conspicuous : here 

 the horns assume a very decided character; and 

 although given to numerous insects, scattered in all 

 the families, are more especially developed in the 

 gigantic beetles forming the modern group of Dy- 

 nastidce. In the soft-winged flying orders, especially 

 in the Lepidoptera (more analogous to birds than 

 is any other), crests take the place of horns, of which 

 the whole tribe of the Noctuidce is a striking example. 

 When, therefore, in a group of animals, we see that 

 horns or crests distinguish the major part, we draw 

 their essential character from that circumstance : 

 but when, in another group, these appendages are 

 only confined so a small portion, we take the 

 essential character from the general peculiarity of 

 the whole, and discriminate these few which are 

 horned as a subordinate assemblage. 



(177.) Another of the most prevalent forms in 

 the animal world is that in which the tail, or the 

 caudal appendage representing it, is excessively 

 developed. In looking, however, to this member, 

 we must carefully note the peculiar sort of develope- 

 ment it presents ; because, although it may be very 

 large in any given number of examples, its form- 

 ation, and consequently its offices, will be totally 



