HABITS 
ORE than any other creatures, dragon- 
flies are dependent on their wings for 
meeting the ends of existence. They 
not only hunt on the wing, but many of 
them also eat and mate on the wing, and 
some of them lay their eggs while flying. 
The larger and stronger species are among 
the fleetest of living creatures. Most of 
their time is spent in pursuit of food or 
of mates. 
In powers of flight they differ, however, enormously. This 
is most easily seen on a hot summer day at the side of a pond 
where many kinds of dragonflies and damselflies are flying together. 
They fly at different levels, somewhat as indicated in the diagram; the 
big darners highest, the little bluets lowest, the others each habitually 
and generally at a rather constant level in between. Many of the 
damselflies move along so close to the surface that it is hard to take 
them in a net without dipping the water. That it is also harder for big 
dragonflies and for birds to take them at the lower levels is doubtless 
the explanation of the habit. Powers of flight in this order of insects 
seem to vary rather directly with size and strength of wing. 
Their ‘hawking’ operations could not escape the notice of that 
good naturalist, Henry D. Thoreau, and there are frequent brief 
entries like this one in his Notebook: 


Large devil’s needles are buzzing back and forth. They skim along the edge 
of the blue flags, apparently quite around this cove and further, like hen harriers 
beating the bush for game.* 
The game they seek is other flying insects. The most direct service 
rendered to man by the dragonfly is doubtless in the destruction of 
many annoying little flies and mosquitoes, some of which, on account 
+ Other observations will be found under the account of the genera and species 
in Part II, especially under the following: on manner of flight, species numbers 
2, 12, 16, 34, 44, 50, 53, 55, 66, 78. 93, 95, 100, 116, 121, 136, 137, 148, 154, 159, 
160, 166, 171, 172, 173, 186, 187, 198, 199, 207, 230, 231, 234, 236, 242, 251; on 
oviposition, species numbers 2, 18, 34, 36, 55, 93, 98, 104, 116, 127, 171, 201, 211, 
217, 225, 230, 242, 251, 254, 258, 261, 358; on feeding, species numbers 7, 116, 
277; on transformation, species numbers 2, 48, 173, 190, 220, 358. 
* Collected Writings: entry for June 10, 1857 
Zi 
