CII. I.] METAMORPHOSES OF INSECTS. 27 



Indeed, in the Alphabet of Insects, Mr. Rennie 

 has not hesitated to give them the name of ears, ob- 

 serving, " As I have httle doubt these organs will 

 one day be proved to be ears, 1 think it will direct 

 attention more decidedly to them by at once term- 

 ing them ears, than by leaving them (their uses) open 

 to all sorts of crude fancies, so easy to form, but so 

 detrimental to correct inquiry." Until, however, it 

 shall be proved, not only that the senses of insects 

 are precisely similar to those of the higher animals 

 (which, from the very great differences in their gen- 

 eral organization, appears to many naturalists to be 

 very doubtful), but also that the antennae are the or- 

 gans of hearing, it must be allowed that the employ- 

 ment of so decided a term as ears must be very im- 

 proper, and really " detrimental to correct inquiry," 

 by leading the student to suppose that the uses of 

 these organs, upon which the most eminent natural- 

 ists are at variance, had been clearly ascertained. 

 Hence, in the following pages, we shall continue to 

 employ the term antennas for these appendages, as 

 being one unlikely to lead to erroneous suppositions. 



The manner in which the surprising change in the 

 size of the butterfly's wings is so suddenly effected, 

 from its small corrugated form until it acquires its 

 full development, is owing to the impulsion either 

 of air or an aqueous fluid, or perhaps of both, into 

 the tubular nervures of the wings ; for although, 

 on looking at these beautiful instruments of flight, 

 we only perceive a covering of richly coloured 

 down, yet on brushing this off and minutely exam- 

 ining the substance of the wing, it will be found to 

 consist of two layers of very thin membrane, be- 

 tween which various veins, nervures, wing-bones, 

 or ribs, as they have been termed, are found dis- 

 posed in a longitudinal direction. Hence, when the 

 insect impels into the minutest ramifications of these 

 nervures of its moist and corrugated wings sufficient 

 fluid to distend the tubes, it follows that the mem- 



