610 EXTERNAL ANATOMY OF INSECTS. 
some of these however, as Odzocerus, Flata, &c.* there 
are no traversing nervures; and these lead to the Cer- 
copide and others in which the longitudinal nervures 
become few, and some are without any, and these ter- 
minate those of this section of the Order in which the 
nervures in question are continued to the margin of the 
wing. We next come to those, Darnis, Centrotus, 
Membracis, &c. in which they are circumscribed a little 
within the apex by a traversing nervure, so that the teg- 
men ends in a margin of pure membrane, and thus some 
approach seems to be made to the Hemelytra, from Ci- 
cada, the most conspicuous genus of this tribe, in which 
the areolets, few in number, like those of Lepidoptera, 
are not formed, except the terminal ones, by traversing 
nervures, but by the ramifications of the longitudinal 
ones; in Chermes the Intermediate Area, which is con- 
nected with the base of the wing by a single nervure, is 
the only part that has any areolets °. 
7. Colour. Orthopterous insects are seldom remark- 
able for tegmina of brilliant colours ; there is in them 
none of that gilding or metallic lustre which so often di- 
stinguishes elytra: they are also frequently less orna- 
mented in this respect than the wings, with which they 
usually form an agreeable contrast. ‘Their reticulations 
and nervures, which are sometimes of a different colour 
from the rest of the tegmen, decorate them considerably : 
a remarkable circumstance belonging to this head attends 
the black tegmina of Blatta Petiveriana ; one has four 
white spots, and the other only ¢hree ; but as one laps 
a Linn. Trans. xii. ti. f. 14. Flata should come before this genus. 
> Of this kind is one of Stoll’s Cigales, t. xxv. f. 141. 
© Prate XXVIIE. Fic. 18. 
