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260 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 important 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 natural and appropriate. These organs deviate still further from the wings of the Coleoptera 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 ημιου the half,) and also hemelytra, the latter used to designate the upper wings when spoken of by themselves. This structure, however, must be looked upon as merely characterising 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, sometimes the half, (as in Lygaeus,) at other times two-thirds, (in Alydus,) and three-fourths in certain Reduvii. Occasionally, it is so extensive as to reduce the membranous portion to a narrow band at the tip,