IMPERFECTION OF INSTINCT. 1G7 



formed and ready for complete action as soon as the imago 

 escapes from its pupa stage. The difference between its pre- 

 vious life as a larva and its new life as an imago, is as great 

 as the difference between the lives of two animals belong- 

 ing to two different sub-kingdoms ; and the complete adapta- 

 tion which all the new class of instincts exhibit to the 

 requirements of this new life, is quite as remarkable as is the 

 adaptation of the new structures to the same requirements. 



Imperfection of Instinct. 



I shall first give a few cases to show that instinct is not 

 an infallible guide to action, and for this purpose shall choose 

 aberrations of those instincts which we should expect to be 

 most fixed, because of most importance to the well-being of 

 the animals or their progeny — I mean the instincts of pro- 

 pagation and the procuring of food. 



The flesh-fly (Musca carnaria) deposits its eggs in the 

 flowers of the " carrion plant " {Stapdia hirsuta), the smell 

 of which resembles that of putrid meat, and so deceives the 

 fly.* Similarly, the house-fly has been observed to deposit 

 eggs in snuff, f 



Again, the Eev. Mr. Bevan and Miss C. Shuttleworth, 

 write me independently that they have seen wasps and bees 

 visiting representations of flowers upon the wall-paper of 

 rooms ; and Trevellian saw the same mistake made by the 

 sphinx-moth.J Swainson in his " Zoological Illustrations," 

 gives ail analogous case in a vertebrated animal; an Austra- 

 lian parrot, whose food is taken from the flowers of the 

 Eucalyptus, was observed endeavouring to feed on the repre- 

 sentatiou of flowers on a cotton-print dress. Likewise, 

 Professor Moseley, F.R.S., informs me that he has noticed 

 honey-seeking insects mistake for flowers the bright coloured 

 salmon flies stuck in his hat while fishing; and Mr. F. M. 

 Burton, writing to " Nature" (xvii, p. 162), says that he has 

 observed the bumming bird hawk-moth [Macroglossa stellar 

 tarum) mistake artificial flowers in a lady's bonnet for real 

 ones. Still more curiously, the naturalist Couch observed a 



• B. Darwin, Zoonomia, i, $ 16, art. 11. Also Kirbj and Spenco, loo.cit., 

 ii, 4»'p , .>, who stair the i.ni on the authority of Dr. Zinken, 



t Zinken, in Chrmar. Mag. der Ento., Bd. I, ui.th. l, § 189. 



X Be6 lloil/.r.iu, 100. til., I, 210. 



