In this vaulted cell the pupa disengages itself little by little from its skin, which first splits up along the head, and then on the thorax. This opening is sufficiently large to enable it to come out of its envelope. It is in the month of September that these insects are particularly abundant, and then the trees and plants are covered with them. Sometimes the froth drips off, like a sort of small rain, from branches which are covered with it. Towards the autumn the females are pregnant. They are then so heavy that they can hardly jump or fly. The males, on the contrary, make prodigious bounds; they throw themselves forward to a distance of more than two yards. They are very difficult to catch, and still more difficult to find again when one has once let them escape. And so Swammerdam calls these insects Sauterelles-Puces (Flea-Grasshoppers), because they jump like fleas.
Fig. 85.—The Froghopper
(Aphrophora spumaria).
All that we have said relates to the Aphrophora spumaria, or Froghopper ([Fig. 85]), an insect common all over Europe, and which Geoffroy calls the Cigale bedeaude.
"It is of a brown colour," says Geoffroy, "often rather greenish. Its head, its thorax, and its elytra, are finely dotted; on these last one sees two white oblong spots. The lower part of the insect is light brown." [27]
We will mention, as it belongs to the group with which we are now occupied, a noxious insect, Iassus devastans, which since 1844 seems to have taken up its quarters in the commune of Saint Paul, in the department of the Basses-Alpes. It sucks the leaves and stalks of cereals, causing them to wither, and may be found even in winter on young corn, but principally in the spring. According to M. Guérin-Méneville, its head is of an ochrey yellow, with the apex marked with black spots; the forehead yellow, elongated, striped with black, as are the legs. The elytra are straw-coloured and spotted with brown. The wings are transparent, and slightly blackened at the extremities. This remarkable insect, which is not more than the twelfth of an inch in length, jumps and flies with great ease.
 | ||
| Fig. 86. | ||
| 1. Hypsauchenia balista. 2. Membracis foliata. | 3. Centrotus cornutus. 4. Umbonia Spinosa. | 5. Bocydium globulare. 6. Cyphonia furcata. |
A small brownish insect, whose strange appearance struck Geoffroy, the historian of the insects of the environs of Paris, may be seen springing over the fern stalks and thistles, in the damp parts of most of the woods of Europe.
Geoffroy calls this insect "le Petit Diable." "Le Petit Diable," he writes, "is of a dark blackish-brown. Its head is flat, projecting but slightly, and, as it were, bent downwards. Its thorax, which is rather broad, has two sharp horns, which terminate in pretty long points on the sides. In the middle of the thorax is a crest or comb, which, prolonged into a sort of sinuous and crooked horn, terminates in a very sharp point, reaching to within one quarter of the extremity of the wing-cases. These—viz., the wing-cases—are dark, with brown veins; and the wings, shorter than their cases, are rather transparent. The insect jumps very well, and is not readily caught."[28]