8 4 
Dragon-flies and Damsel-flies 
each female. Needham counted 110,000 eggs in a single egg-mass of Libellula. 
Sometimes the eggs may be laid on wet mud or attached to moist water- or 
shore-plants. The damsel-flies and a few of the dragon-flies insert the eggs 
in the stems of dead or living water-plants below the surface of the water. 
To do this they have to cling to the stem, with the abdomen or sometimes 
the whole body under water, and cut slits in it with the sharp ovipositor. 
The eggs are sometimes laid on submerged timbers and moss- or alga-covered 
stones. Kellicott observed females ol Lflf^ a^^^i^- 4 a-<lamsel-fly abundant 
along Lake Erie) to remain wholly under water for from five to fifty-five 
minutes at a time. These females were accompanied by males which also 
stayed under for similar lengths of time. 
The eggs hatch after various periods, depending on the species of dragon¬ 
fly and on the time of year of oviposition. In midsummer Needham found 
the eggs of some species to hatch in from six to 
ten days, while others laid in autumn did not hatch 
until the following spring. In the same lot of eggs 
the period of incubation may vary even in midsum¬ 
mer from a week to more than a month. 
From the eggs come tiny, spider-like nymphs 
with long, slender legs, thin body, and no sign of 
wings. Even in the largest dragon-fly species the 
just-hatched young are only about one-twelfth of 
an inch long, while the nymphs of the common 
Libellulas are only one-twenty-fifth of an inch long 
at hatching. They begin their predatory life, con¬ 
fining their attention at first to the smaller aquatic 
creatures, but with increasing size and strength 
and confidence being ready to attack almost any of 
the under-water dwellers. Even fish are seized by 
the larger nymphs, Needham having seen the 
nymphs of one species seize and devour young 
brook-trout as long as themselves. 
The young of different species differ consider¬ 
ably in size, shape, and duration of their nymphal 
existence. The nymphs of some species require 
more than a year to develop into adults, while those of some others are ready 
to transform in a few months, not a few dragon-fly species having two gener¬ 
ations a year. The one-year life cycle, however, is usual among the more 
familiar dragon-flies, the eggs laid during midsummer hatching in late sum¬ 
mer, the nymphs hibernating and being ready to emerge the following sum¬ 
mer. Needham thinks that the damsel-flies have a number of broods in 
a season, the processes of transformation and oviposition beginning as soon 
Fig. 115. —The young 
(nymph) of a damsel- 
fly (narrow-winged dra¬ 
gon-fly), Lestes sp. The 
three leaf-like processes 
at the tip of the abdo¬ 
men are gills (Twice 
natural size.) 
