THE MASTERY OF THE AIR 235 
It is useful for us to know that these insects 
cannot fly far, for then we can protect our- 
selves to a great extent by taking care that 
their breeding-places—stagnant water in the 
case of the mosquito, manure- and refuse- 
heaps in the case of the house-fly—are not in 
the immediate neighbourhood of our dwell- 
ing-houses. 
But many other insects have great powers of 
flight. The beautiful, big, rainbow-coloured 
or sapphire-blue dragon-flies, which are so 
conspicuous on our moors in sunny weather, 
fly all day, and sometimes cover two or three 
miles. They catch their prey of smaller insects 
on the wing, and can suck the juices from them 
without ceasing to fly. Their legs have be- 
come so weak that they are of no use at all for 
walking, but are used for perching, and for 
catching and holding the prey. The bees, too, 
as we may see for ourselves, are capable of 
strong and rapid flight, and it has been proved 
that their daily business of honey-getting may 
lead them several miles from the hive. 
The power of flight in insects sometimes 
rises to a very high pitch. A wasp has been 
known to fly tail-foremost for a quarter of an 
hour in front of a bicycle. Dragon-flies, which 
