After another moult the insect passes into the passive nymphal or " pupal " stage, during which it takes no food and rests in some safe hiding-place, such as the soil at the base of its food-plant or the hollow of a leaf-stalk.
But examples are not wanting of a more or less complete resting habit during the latest nymphal instar.
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.
- a, Cast-off nymphal skin of Bed-bug (Cimex lectularius); b, Second instar after emergence from a; c, The same after a meal.
In all Hemiptera the wing-rudiments develop externally on the nymphal cuticle, but in some families - the cicads for example - the young insect (fig.
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.
Hagen not to be functional in the adult insect - they are merely survivals from the aquatic nymphal stage.