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IX. The studf/ of mimicry {Batesian and Milllerian) hy 

 tem'perat'urc exjyerinients on two Tropical butter- 

 flies. By LiEUT.-CoLONEL N. Mandees, R.A.M.C, 

 F.Z.S., F.E.S. 



[Read February 7th, 1912.] 



Plate XLI: 



These experiments were undertaken when I was becom- 

 ing impressed with the conviction that Natural Selection 

 was not the prime factor in causing those remarkable 

 resemblances among certain tropical butterflies which are 

 usually classed as instances of Batesian or Milllerian 

 mimicry. 



They are not so numerous as I could wish, but as I am 

 unlikely to be able to continue them, I bring them forward 

 as they may be of assistance to others in future work in 

 what I believe to be a fruitful field. 



The insects dealt with form the best known case of 

 mimicry among butterflies ; the classical example of 

 Batesian mimicry, viz. Danais chrysippus (model), and 

 its two forms dorippus and alcipptus, and Hypolimnas 

 misip2nis (mimic) with its trimorphic female resembling 

 D. chrysippus, dorippus, and alcippns respectively. 



I have chosen these two butterflies as they are almost 

 universally known to entomologists; they are not subject 

 in any way to seasonal dimorphism ; and they were com- 

 mon at Colombo where these experiments were carried 

 out. The material of these experiments has been pre- 

 sented to the Hope Department of the Oxford University 

 Museum, where it will be accessible to all naturalists. 



It will be as well to devote a few words to the life- 

 history of these butterflies as I have observed them in 

 Ceylon. 



Danais chrysippus. 



Though the natural enemies of the perfect insect are 

 few in number it is by no means exempt from destruction 

 in its earlier stages. It is difficult to estimate the pressure 

 of enemies during the egg stage, but I believe there is a 

 gradual decrease of mortality from egg to imago in all 



TKANS. ENT. SOC. LOND. 1912. — PART II. (oCT.) 



