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 De 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 



