After a prolonged aquatic larval and nymphal life-history, the winged insect appears as a sub-imago, whence, after the casting of a delicate cuticle, the true imago emerges.
Hagen not to be functional in the adult insect - they are merely survivals from the aquatic nymphal stage.
CUCKOO-SPIT, a frothy secretion found upon plants, and produced by the immature nymphal stage of various plant-lice of the familiar Cercopidae and Jassidae, belonging to the homopterous division of the Hemiptera, which in the adult condition are sometimes called frog-hoppers.
In all Hemiptera the wing-rudiments develop externally on the nymphal cuticle, but in some families - the cicads for example - the young insect (fig.
But examples are not wanting of a more or less complete resting habit during the latest nymphal instar.
Again, in Ornithodorus monbata, which is parasitic apparently only at night, the young does not hatch from the egg until it has attained the nymphal stage.