A hidden impulse rent the veil,
Of his old husk, from head to tail,
Came out clear plates of sapphire mail.

'From head to tail,' for the nymph-cuticle splits lengthwise down the
back, and the head and thorax of the imago are freed from it (fig. 8
_a_), then the legs clasp the empty cuticle, and the abdomen is drawn
out (fig. 8 _b, c_). After a short rest, the newly-emerged fly climbs
yet higher up the water-weed, and remains for some hours with the
abdomen bent concave dorsalwards (fig. 8 _d_), to allow space for the
expansion and hardening of the wings. For some days after emergence the
cuticle of the dragon-fly has a dull pale hue, as compared with the dark
or brightly metallic aspect that characterises it when fully mature. The
life of the imago endures but a short time compared with the long
aquatic larval and nymphal stages. After some weeks, or at most a few
months, the dragon-flies, having paired and laid their eggs, die before
the approach of winter.

[Illustration: Fig. 8 _a, b_. Dragon-fly (_Aeschna cyanea_). Two stages
in emergence of fly from nymph-cuticle. From Latter's _Natural
History_.]

[Illustration: Fig. 8 _c_. Dragon-fly emerged, wings
expanding. From Latter's _Natural History_.]

[Illustration: Fig. 8 _d_. Dragon-fly (_Aeschna cyanea_) with
expanded wings.]

The life-story of a may-fly follows the same general course as that just