takes place the nymph has foretastes of the aerial mode of breathing which it will practise when the perfect stage shall have been attained. The emergence of the dragon-fly from its nymph-cuticle has been described by many naturalists from de Reaumur (1740) to L.C. Miall (1895) and O.H. Latter (1904). The nymph climbs out of the water by ascending some aquatic plant, and awaits the change so graphically sketched by Tennyson: 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.]