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 arigle, formed 
by the meeting of the anterior and posterior margins, 
sometimes called the apex or apical angle ; the 
posterior angle 3 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 hear, both to certain 
bodily parts of other animals, and of insects them- 
selves. Jurine 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 trachece, 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 
opinion, a German naturalist, M. Oken, comes to 
