ENTOMOLOGY. , 115 



with the thorax is called the base; the extremity 

 opposite to this is the posterior margin ; the anterior 

 or exterior margin, (sometimes called the costa,*) is 

 that which is most advanced in flight, lying in the 

 direction of the head, and the interior margin is the 

 one opposite to it. The angles formed by the meet- 

 ing of these margins are, the anterior angle, formed 

 by the meeting of the anterior and posterior margins, 

 sometimes called the apex or apical angle; the 

 posterior angle, formed by the posterior and interior 

 margins ; in the hinder wings this is frequently termed 

 the anal angle. 



It may relieve the tedium of descriptive and tech- 

 nical details, which are often unattractive although 

 indispensable elements of knowledge, to allude for 

 a moment to the play of fancy in which authors 

 have indulged in regard to the analogical relations 

 which the wings of insects bear, both to certain 

 bodily parts of other animals, and of insects them- 

 selves. J urine compared them to the wings of birds, 

 and in this he was followed by Chabrier. Latreille, 

 after a laborious investigation, arrived at the unex- 

 pected conclusion, that they are true feet, merely 

 modified in their situation and uses ! Shortly after, 

 M. Blainville discovered that wings are nothing else 

 than exterior tracheae, an opinion which Latreille sub- 

 sequently inclined to adopt. Nearly at the same 

 time, our countryman MacLeay, conceived the no- 

 tion that they represent four of the legs of the de- 

 capod Crustacea. Amid this perplexing diversity of 

 pinion, a German naturalist, M. Oken, comes to 



