
HEMIPTERA. 117 
It isin the froth that the larvae change into pups, and do not leave 
their habitation to undergo their final metamorphosis. They have 
then, says De Geer, the art of causing the froth inside to evaporate 
and dry up, in such a manner as to form a space inside the mass 
of froth, in which their bodies are entirely free. The exterior froth 
forms a roof closed in on all sides, under which the insect lies 
quite dry. 
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, when 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 gravid. They are then so heavy, 
that they can hardly jump or fly. The males, on the contrary, 
make prodigious bounds; they throw themselves sometimes 
forward to a distance of more than two yards. They are very 
difficult to catch, and still more difficult to find again when one 
thas once let them escape. And so Swammerdam calls these in- 
sects Sauterelles-Puces (Flea-Grasshoppers), 
because they jump like fleas. 
All that we have said relates to the Cercopis 
spumaria, or Froghopper (Fig. 85), an insect 
common all over Europe, and which Geoffroy 
ealls the Cigale bedeaude. 
“Tt is of a brown colour,” says Geoffroy, “ often rather greenish. 
[ts head, its thorax, and its elytra, are finely dotted ; on these last 
me sees two white oblong spots.. The lower part of the insect 
s light brown.” * 
We will mention, as it belongs to the group with which we are 
low occupied, a noxious insect, the Jassus devastatans, which since 
[844 seems to have taken up its quarters in the commune of Saint 
Paul, in the department of the Basses-Alpes. It sucks the 
eaves and stalks of cereals, causing them to wither, and may be 
ound even in winter on young corn, but principally in the spring. 

Fig. 85.—The Froghopper 
(Cercopis spumaria). 
* “ Histoire abrégée des Insectes, dans laquelle ces animaux sont rangés dans un 
rdre méthodique.” In 4to, au VII. de la Republique, tome i. p. 416, 

