SYSTEM OF INSECTS. 377 
and the last, Homoptera*. Dr. Leach, observing that 
very considerable differences take place both in the eco- 
nomy and structure of Heteropterous and Homopterous 
insects, followed De Geer in considering them as sepa- 
rate Orders, which he has called Hemiptera and Omo- 
ptera, and in which he has been followed by Mr. Mac- 
Leay; who, however, with his usual accuracy and judg- 
ment, has restored the aspirate to the latter name>. Their 
agreement in having a promuscis, or instrument of suc- 
tion, with a jointed sheath, at present induces me to hesi- 
tate as to the propriety of their separation, and to consi- 
der them as forming secondary rather than primary sec- 
tions of the Class. ‘That you may be enabled to judge 
for yourself upon this subject, I will state the principal 
features in which they differ. In the first place, the He- 
teropterous section usually sucks the juices of animals, 
and the Homopterous, those of plants ; in the former, the 
Hemelytra, besides their different substance, as well as 
the wings, cross each other ; while in the latter, the organs 
of flight are defiexed, and do not lap over each other at 
all. The antennee also of the one are often long, and do 
not terminate in a bristle; while in the other, with few 
exceptions, they are very short and setigerous. In the 
Heteroptera the body is depressed and flat, in the Homo- 
ptera convex and thick. In the former, the scutellum is one 
of the principal features of the trunk; in the latter, not at 
allremarkable*. Other differences in the structure, both 
a If considered as suborders, their denomination should not ter- 
minate precisely as that of Orders. Perhaps Hemipterita and Hete- 
ropterita might be an improvement. 
> Hor. Entomolog. 374—. © Vou. III. p. 596. 
