328 THE PLACE OE MIMICRY 



inexperienced enemies is facilitated, and insect life saved 

 in the process. Each species which falls into a group with 

 Common Warning or Synaposematic Colours 1 contributes 

 to diminish the destruction of the other members. It is 

 obvious that the amount of learning and remembering, 

 and consequently of injury and loss of life involved in 

 these processes, are reduced when many species in one 

 place possess the same Aposematic colouring, instead of 

 each exhibiting a different ' danger-signal '. 



It has been pointed out that this struggle is in reality 

 far more severe than has been supposed. At each 

 breeding season a fresh wave of young enemies is sent 

 forth, takes its toll of insect life, and, except for an 

 insignificant fraction, perishes in the struggle with its 

 own foes. 2 



Before proceeding to discuss Synaposematic Resem- 

 blance in some detail, adducing many examples, I desire 

 to state as prominently as possible that a Miillerian, as 

 opposed to a Batesian, interpretation is suggested in no 

 positive or dogmatic spirit. Detailed researches into 

 the subject are very recent, while new material and the 

 record of fresh observations are continually appearing. 

 Hence the explanation of special examples must in many 

 cases be regarded as provisional. My friend, Mr. G. A. K. 

 Marshall, would consider that a Batesian or Pseud- 

 aposematic interpretation is more probable for many of 

 the examples. On the other hand, so far as I can judge 

 from existing evidence, I believe — and at any rate for 

 the most part Dr. Dixey agrees with me — that all of 

 them fall under the Miillerian Hypothesis of Common 

 Warning Colours. 



i. The Mathematical Statement of the Advantage 

 Conferred by Perfected Miillerian Resemblance. — The 

 precise statement of advantage was made by Mr. Blak- 

 iston and Mr. Alexander, of Tokio. ' Let there be two 



1 These terms were introduced in a note, dated June 14, 1897, to the 

 report of the discussion on Dr. Dixey's paper on Mimetic Attraction in 

 Trans. Ent. Soc, Lond., 1897, p. 317. See Proc. Ent. Soc, Lond., 1897, 

 p. xxix, n. 



2 Proc. Ent. Soc, Lond., 1903, p. lxv; see also pp. 16 7-8 of the present 

 work. 



