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WALTEK KIDD, M.D., F.Z.S., ON 



Then again Cole mentions cold as being a destructive factor in 

 the killing of cei'tain species in primeeval times. I do not dispute 

 that statement, but I have visited some of the most exposed coasts 

 and I know Iceland round all three sides of the coast, and I can 

 safely state that cold is not the most destructive factor in killing 

 insects. It is the utter want of shelter from snow or rain that 

 would cause them, in the transition period, to rot, and we have the 

 testimony of entomologists now to prove that heat is quite as pre- 

 judicial to the preservation of life as cold. 



There are two or three other points to which I would draw 

 attention. I suppose we are all content to agree that the evolution 

 of to-day can evolve something. Experimentalists can do some- 

 thing in that way by different treatment and different conditions^ 

 I know from my own collection how the sizes and tints of different 

 specimens may be varied by their food, and it remains to be seei^ 

 whether those different tints or markings and lines remain perma- 

 nent. Feed the caterpillar on dark green leaves and you get a 

 perfect yellow moth. Feed the same caterpillar on light green 

 leaves and you have white and so on. Bat you must go on season 

 after season, or they will hark back to their original ancestoi\ 

 On the other hand, look at the evident purpose of design and see 

 what it does for the creature. 



Perhaps few of you have seen the Larentla ccesiata, of a delicate 

 soft grey, which is found on the grey slate rocks of the Cambrian 

 coast of the Campbell country in Argyleshire and the lava ditto in 

 the S.W. of Iceland, upon which the perfect insect can lie so 

 concealed from its natural foes on the surface of the boulders that 

 you cannot tell the living insect fi'om the inanimate stone. 



When I see these things I note that Providence has adapted the 

 colour of the insect to its natural environment, and then I am 

 prepared to say, " Yes, this is the finger of God.'' 



The Chairman. — I will now ask Dr. Kidd to reply. 



The Author. — I am very grateful to those who have spoken for 

 their kind agreement with most of the paper. 



It would be only presumption in me to refer to anything that 

 Dr. Beale has said. I am most thankful for the interesting" 

 suggestions he has made — more especially for that point on the 

 absence of any analogy between the electrical organism of animals, 

 such as the gymnotus, and the electrical machines formed by 

 man. That is a most valuable point, but the subject is far too 

 deep for us to go into to-night. 



In regard to Dr. Walker's inquiry, respecting butterflies, I am 



