HEMIPTERA. 119 
Geoffroy calls this insect “le Petit Diable.”’ “Le Petit Diable,” 
says he, “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. It jumps very well, and it is not 
éasy to catch it.”’* 
The Petit Diable of Geoffroy is the Centrotus cornutus of modern 
naturalists. This curious little insect belongs to a strange and 
remarkable group, whose thorax takes the most extraordinary and 
most varied forms, as may be seen in Fig. 86, which represents, 
somewhat magnified, many of these insects. Nearly all inhabit 
Guyana, the Brazils, and the islands of Florida. 
We will now examine one of the most interesting groups to 
study from different points of view—that of the Plant-lice. 
These insects have for a long time attracted the attention of 
- observers. ‘They are so abundant that all our readers have seen 
them, and there are few plants in our fields or gardens which 
do not nourish some species. How often does one hesitate in 
gathering a rose or a bit of honeysuckle, for fear of touching the 
unattractive guest of those charming flowers ! 
During the whole of the summer, one sees on the branches, on 
the leaves, but principally on the young shoots of the rose-tree, 

Figs. 87, 88.—Winged Aphides, or Plant-lice (magnified). 
large companies of green plant-lice, which subsist on the sap of 
the tree. Some are provided with wings (Figs. 87, 88), others are 
* “ Histoire abrégée des Insectes, dans laquelle ces animaux sont rangés dans un 
ordre méthodique.” In 4to., an VII. de la République, tome i., p. 423. 
