7 8 
Dragon-flies and Damsel-flies 
streams impregnated with sulphur from sulphur springs. Nor do dragon¬ 
flies like cold weather. Although a few species are found in the far North 
(recorded at 70° N. in Norway, 65° N. in Alaska, and 63° N. in Siberia) 
and a few at high cold altitudes (as high as 10,000 feet) on mountain flanks, 
the great majority of them need considerable temperature for growth and 
development and even for activity during adult life. Calvert says that but 
one species is known which regularly passes the winter in adult stage, and 
that most dragon-flies live as adults from 
but twenty-five to forty-five days, and * 
these in the summer. In California, where 
the winter temperature at sea-level only 
occasionally falls to 32 0 F., adult dragon¬ 
flies can be found in most of the months 
of the year. 
The adult dragon-flies are to be seen 
pursuing their prey, like hawks, with 
swift darting flights over ponds, along 
streams, and even scattered widely inland 
over fields and in woods. A few kinds 
have a liking for the vicinity of houses. 
Needham, a careful student of these 
insects, has found that the hunting region 
above and along the shores of a pond may 
be imaginarily divided into zones one 
above the other, each zone characterized 
by the presence of a few particular 
dragon-fly species. “So, in fact,” he writes, “we find the smaller damsel- 
flies flying over the water in a straight course an inch or less above the 
surface, and rarely venturing higher; the larger damsel-flies a little higher; 
the amber wings at an average of about six inches; the larger skimmers 
a foot or more from the surface, and upland skimmers and darters still 
higher. One has only to stand a little while by some small area of water 
where all these are flying to see that each keeps rather closely to his proper 
altitude. Why do damsel-flies keep so close to water? The reason is 
not far to seek. Dragon-flies eat one another—the strong destroy the 
weak. If to venture up into the altitude of the larger species means to run 
the risk of being eaten, we can readily see why the damsel-flies should 
stay down below. The hawk may roam the air at will, but sparrows must 
keep to the bushes.” 
We think of dragon-flies, as of albatrosses and Mother Carey’s chickens, 
as being always on the wing. They catch their prey while flying, eat it 
while flying, mate while flying, and some of them deposit their eggs while 
Fig. 113. — Damsel-flies 
winged dragon-flies). 
size; from life.) 
(narrow- 
(Natural 
