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double, and sometimes three or four times, the length of those 
of the female. In many other insects it is a difference of structure 
that so remarkably distinguishes the male antenne. They are 
more composite than in the female, pectinated or plumose, or 
differentiated in some other way. Most persons must have noticed 
the beautiful feathered antennz of the various species of gnats 
that often swarm in our windows during the summer months. 
These are the males ; the antennz of the females being perfectly 
simple and unadorned, setaceous, or little more than bristles. 
Now this circumstance makes it not improbable that the antenne, 
considered generally, have their use, or one of their uses, in the 
relation of the sexes to each other. The Longicorn before us is 
often found under the bark, or in the hollows, of decayed trees, 
and the long antenne of the male, perhaps in connection with 
some peculiar sense they possess different from any known to 
us, may assist in discovering the spots where the females are 
concealed. 
This, however, is mere conjecture ; and conjectures carry us but 
a short way towards the explanation of the multiplied phenomena 
of the animal kingdom. The day is gone by when final causes 
were appealed to as supplying reasons for this structure or that. 
Final causes lie entirely outside science. This was long ago 
perceived by Bacon, who asserts that “so far from being 
beneficial, they even corrupt the sciences, except in the intercourse 
of man with man.”* And his dictum has only been more and 
more confirmed as science has gradually advanced from his day 
to the present, in which we have all Darwin’s works combining 
to open up an entirely different line of thought. All that we 
can say on the subject of final causes is—that we believe the 
whole world to he ever working for some higher purpose than 
any we can thoroughly understand at present; that it forms an 
harmonious whole, undeniably the result of a Great First Cause ; 
* “ Advancement of Learning.’ 
