CHAPTER VI 
THE MASTERY OF THE AIR 
What Getting into the Air meant—The Flight of Insects—Why 
are there so many Insects?—The Flying Dragons—The 
Flight of Birds—Different Kinds of Flying in Birds—Migra- 
tion the Climax—Thce Fourth Solution of Flight—Fitnesses 
of Birds and Bats—Attempts at Flight—Gossamer Spiders. 
GE after age life has been slowly creeping 
upwards, becoming finer and finer in its 
forms, and with greater freedom in its ways. 
And who shall say that this progress is going 
to stope In any case the fact is that for mil- 
lions of years there has been among animals 
a search after new kingdoms to conquer, some- 
times under the spur of necessity, sometimes 
prompted by a spirit of adventure. So after 
the open sea and the shore of the sea, the fresh 
waters and the dry land, we come to the air. 
The last haunt to be conquered was the air. 
Of course there are no animals quite aerial. 
These dancing May-flies, they spent two or 
three years as aquatic larve on the floor of the 
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