228 INIr. E. Newman's Memorandum 



formed : he may, inclecd, accumulate evidence as to the nature 

 of the function performed, until such accumulated evidence be- 

 comes highly satisfactory, but he cannot positively infer the func- 

 tion performed from the quality and characters of the organ per- 

 forming it : witness the antenocB of an insect, the real use of 

 which is still a moot question, suspended perhaps for the moment, 

 but only on account of its difficulty. 



Now taking a pr'imd fade view of the wing of a butterfly, de- 

 nuded of its lepidia, it appears to consist, first, of a fabric of the 

 most delicate filmy, powerless character ; indeed, so excessively 

 attenuated, that a small portion, detached from the rest, infallibly 

 floats awhile on the air ; and, secondly, of a strong and durable 

 framework, on which the filmy fabric is extended and suspended, 

 as paper on the frame of a kite or glass in a window or greenhouse. 

 Seeing the wing, thus composed of two distinct elements, capable 

 of sustaining powerful and continued motion, and having observed 

 and considered these phenomena, 1 conclude that the framework 

 is the support of the membrane, and at the same lime is also the 

 instrument by means of which its movements are accomplished ; 

 and I arrive at this conclusion, not speculatively or hypothetically, 

 but involuntarily, and because the mind ignores every other. 

 Determined, however, to take nothing for granted, in a conclusion 

 so opposite to the received opinions and habitual usages of all my 

 Entomological friends, I secured a number of specimens of Pieris 

 Brassicce, when strongest on the wing : I separated the leading 

 wing-rays with the point of a penknife, in some near the basal, in 

 others near the distal extremity of the ray : in every instance the 

 distal portion of the wing fell powerless ; the balance was de- 

 stroyed, and the poor mutilated insects, in their futile attemps to 

 fly, rolled over and over on the ground, until, out of compassion, 

 I terminated their tumbling. Here then was evidence, Jlrst, that 

 the filmy membrane was supported by the rays, and therefore 

 that the rays were organs of support : and, second!//, that their 

 mutilation prevented the insects from flying, and, therefore, that 

 they were organs of support subserving the power of locomotion. 

 Still I can imagine that some strenuous advocate of either of 

 the received hypotheses may contend that the motive power re- 

 sided in the membrane, but was deprived of its efliciency by the 

 injury it had received on my separating the rays. This argument 

 I am able to invalidate by one of those coincidences which often 

 appear curious and unaccountable. It happens, that many years 

 ago I made, and luckily published, an observation which bears, 

 and I diink conclusively, on the subject. I found, in Darenth 



