HEMIPTERA. 
261 
and in a numerous race it may be said to occupy the 
whole surface, rendering the hemelytra very similar 
to the tegmina of Orthoptera. On the other hand, 
the transparent portion often encroaches on the region 
of the other, to a greater or less extent, and in Coreus, 
Tingis, Aphis, &c., the whole is nearly of a uniform 
membranous consistency. 
This want of uniformity has occasioned difference 
of opinion among authors respecting the position, 
affinities, and constitution of the Hemipterous order. 
Linnaeus confounded it with the Orthoptera ; others, 
in order to avoid the impropriety of associating gnaw- 
ing insects with suctorial ones, effected their separa- 
tion ; and thinking it also improper to unite such as 
have half membranous upper wings with those in 
which they are wholly coriaceous, formed two sepa- 
rate orders under the names Hemiptera and Homop- 
tera. This was done by He Geer, in which he was 
followed by Dr. Leach and Mr. MacLeay. Although 
the differences in the texture of the wings are cer- 
tainly important, and it has the appearance of incon- 
sistency not to take them into account in an arrange- 
ment where they are professedly assumed as indicat- 
ing primary sections, more especially when they are 
connected, as in this instance, with corresponding 
differences in economy, it has notwithstanding been 
generally thought inexpedient to admit the separa- 
tion alluded to. The transition from a corneous to 
a membranous texture, is certainly so gradual, that 
it would be difficult to fix where the line of demarca- 
tion should be drawn ; all the species agree in the 
