{ xlvi ) 



the frog, the co-existence of bright colovirs and inedibility is 

 accidental, or the result of climatic conditions, or even that the 

 inedible qualities are the sources of the bright colouring. Then 

 for the sake of further argument let us suppose that all such 

 cases have arisen from one of these causes, and we are faced 

 with the difficulty that Pcopilio mero2)e, for instance, can produce 

 from one batch of eggs the typical male, and the trophonms, 

 cenea, and the black and white forms of female, all entirely 

 different in appearance, the females not resembling the males 

 in the least, and each closely i-esembling a common inedible 

 Danaid, all of which surprising and varied results are achieved 

 by either accident, similar climatic conditions, or distasteful 

 pigments of the existence of which there is no evidence. I 

 must confess that I find it harder to believe all this than that 

 birds either do or once did exercise a powerful selective 

 influence over buttei^flies. The question of snakes is next con- 

 sidered. In Brazil, we are told that eight species of harmless 

 snakes mimic the same number of species of Elaps. Then, as 

 if to counterbalance this unfortunate evidence, it is pointed 

 out that three harmless genera mimic the poisonous genera and 

 the latter preji on the former, so that they are not protected 

 except from birds. But surely whilst being protected from 

 birds and mammals, they are protected from their poisonous 

 enemies by their resemblance to them, unless the poisonous 

 ones prey on each other. The case is a complicated one, and 

 appeai^s to exhibit protective and aggressive resemblance 

 respectively in the two genera, but brought about by the same 

 means. The balance of nature has been reduced to a fine 

 point. 



In the next section the author cites a case in which a brown 

 Euplosa, a Danais, and a Hyjjolimnas, all much alike, are 

 observed to fly together. Mr. G. F. Mathew maintains that 

 all these three genera are avoided by birds, and the case is 

 given as one to which the Miillerian theory is therefore inap- 

 plicable. I cannot help thinking, however, that the case is one 

 to which the Miillerian theory precisely applies, and the para- 

 graph only goes to confirm Professor Meldola's contention 

 that Professor Packard did not understand the Miillerian 

 hypothesis at all, 



