260 SYSTEMATIC ARRANGEMENT. 



formed for sucking. We have already described the 

 oral tube of Butterflies and Moths,, the only tribes so 

 provided to which we have had occasion to advert. 

 In the others, it presents a very different appearance, 

 and likewise performs functions to which it is not 

 adapted in these. Considered in relation to this im- 

 portant structural peculiarity, the Hemiptera would 

 require to be associated with the other orders similarly 

 distinguished ; but an arrangement which assumes 

 the organs of flight as its regulating principle, points 

 out the situation now assigned to it as the most natu- 

 ral and appropriate. 



These organs deviate still further from the wings 

 of the Col eoptera than those of the order last described. 

 The upper pair may be considered as divided into 

 two parts ; the anterior portion stiff and corneous, 

 resembling elytra, the terminal portion membranous 

 and more or less transparent. Hence the name 

 Hemiptera or half-wings, (from TJ/A/O-J the half,) and 

 also hemelytra, the latter used to designate the upper 

 wings when spoken of by themselves. This struc- 

 ture, however, must be looked upon as merely char- 

 acterising certain typical species, for the deviations 

 from it are numerous and important. The extent 

 of the horny portion of the hemelytra is liable to 

 great variation in different genera. In most instances, 

 it occupies about a third part of the surface, some- 

 times the half, (as in Lygaeus,) at other times two- 

 thirds, (in Alydus^) and three-fourths in certain Re- 

 duvii. Occasionally, it is so extensive as to reduce 

 the membranous portion to a narrow band at the tip, 



