410 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, 1891. 



We do not know exactly what the Chelydrus was. Nicander 

 describes it as a kind of snake ; some think it was a kind of tortoise ; 

 anyhow it was supposed to be injurious to the flock. 



I will conclude by giving you a modern recipe for incense which 

 appeared in a recent issue of the "Chemist and Druggist' ' news- 

 paper : — 



Olibanum 6 ounces. 



4 



Dry storax ...3 „ 



Benzoin 3 „ 



Myrrh 1 ounce. 



Cascarilla 1 ,, 



Lavender flowers ... 2 ounces. 

 Powder coarsely and mix. 



PROTECTIVE MIMICRY. 



By Mrs. W. E. Hart. 



{Mead before the Bombay Natural History Society on 27th July, 1891.) 



The particular form of mimicry I propose to discuss is that similarity 

 iu appearance borne by creatures of one species to those of another 

 which enjoy some special immunity from attack by reason of the 

 possession of some peculiar quality not possessed by the imitators. It 

 is, of course, involuntary, and the result of evolution through long 

 time, perpetuating and intensifying, until they become permanent 

 and specific, accidental and variable resemblances which have proved 

 useful in the struggle for existence. The instances, perhaps, most 

 familiar to us in India are those of some common but very curious 

 and interesting species of butterflies, which being edible themselves, 

 and on that account liable to attack by insectivorous enemies, 

 resemble in coloration and habit of flight certain other species 

 which, by reason of their unpleasant taste and smell, are avoided 

 rather than sought by the natural enemies of their race. Before 

 proceeding to consider instances in detail, the fact is worthy of notice 

 that this kind of mimicry seems to be far commoner among tropical 

 than among English butterflies. The reason would be an interesting 



