HEMIPTERA. 
2 65 
The composite eyes present nothing very peculiar 
in this order. In general they are rather of large 
size, and at times placed very prominently. In the 
genus Aleyrodes there appear to be a pair on each 
side. Stemmata exist in most of the genera, hut in 
some no trace of them can be observed. They are 
of remarkable size in Reduvius, almost equalling the 
dimensions of composite eyes, and seem to be wanting 
in Naucoris, Notonecta, Nepa, and some other tribes. 
When two in number, (which is frequently the case 
among the Hemiptera,) they are sometimes placed 
rather behind the eyes, at other times on the crown 
of the head, (as in Cercopis, Ledra, &c.) and occa- 
sionally (as in the Fulgoridse,) between the eyes and 
the antennae. In the genus Jassus they present the 
singular anomaly of being placed under the head. 
Sometimes they are remote from each other, (Scu- 
tellera, Edessa, &c.) at other times with their edges 
almost touching, (Reduvius, Sic.) In shape also they 
offer some differences, the usual round form being 
exchanged, in Fulgora serrata, for an oblong with a 
longitudinal impression ; in another example of the 
same genus, (Fulgora diadema,) the depression is 
circular. In the genus just named, the ocelli deviate 
in another respect from their ordinary appearance, 
being, instead of the usual black or hyaline colour, of 
a fine yellow in F. laternaria, and white in F. Cande- 
laria. In some kinds of Cicadee they are red. 
The antennas vary greatly, as will appear from the 
descriptions afterwards given of them as aiding in 
distinguishing the different families. In the homop- 
