% EXTERNAL ANATOMY OF INSECTS. 611 
over the other, the symmetry of the arrangement is pre- 
served: the Homopterous Hemiptera are more distin- 
guished in this respect, and some of the Fulgoride imi- 
tate the Lepidoptera both by their ocelli and spots: Ful- 
gora laternaria, Candelaria, serrata, and Diadema, 
sufficiently exemplify this remark, as do several Flate 
likewise?. 
We may observe here—that tegmina are more calcu- 
lated for flight than elytra, both from their thinner sub- 
stance, and from the angle that their Anal Area, and 
often the Costal, forms with the rest of the tegmen ; a 
circumstance which, in wings, M. Chabrier thinks pre- 
sents some facilities in that kind of motion. 
il. Hemelytra®. ‘The next species of wing-covers, 
which though varying in the substance of their base, ter- 
minate in a part distinct from the three areas, consisting 
in almost every case of mere membrane, peculiar to the 
Heteropterous Hemiptera, are called hemelytra, or half 
elytra :—this term was also formerly employed, but cer- 
tainly incorrectly, to denote tegmina. I shall consider 
them with respect to such of the particulars noticed un- 
der the former heads as apply to them, but without re- 
peating them formally. 
1. As to their substance, they must be separately con- 
sidered with regard to their base and apex. In various 
instances the base, or part consisting of the three areas, 
is almost corneous, as in Cydnus Morzo and bicolor, bugs 
not uncommon with us, and many others * ; in these cases 
* Stoll Cigales t. i. f. 1. t. x. f. 46. t. xxix. f. 170. t. v. f. 22. t. iv. 
f. 19. &e. > Pirate X. Fic. 3. 
© In Latreille’s whole genus Pentatoma, including several Fabrician 
DRG 
