STRAY NOTES ON MIMICRY. 33 



on the nest ; but, so far as I can ascertain, this bird has never 

 yet been heard to mimic the note of even another genus, and 

 still less would it be likely to reproduce the note of a reptile, 

 and a note which probably it had never once heard. For Snakes 

 do not hiss, as birds sing, for amusement or occupation. Pro- 

 bably they never hiss at all, except in combat. This is at least 

 true of the Common Snake (natrix), and the Viper (berus), 

 both of which I have had (numbers of them) in captivity. The 

 Common Snake, even when the sexes unite, utters no audible 

 vocal sound, and, when angry with another of its species, it only 

 shakes or rattles its tail a little ; and the Viper seems to be 

 equally silent. Both of these animals make much more noise by 

 their rustling through herbage than by their vocal efforts, except 

 on the special occasion of combat. I have seen the Common 

 Snake feed, say, a thousand times, and never heard a hiss from it 

 then, though sometimes there would be a slight expulsion of air, 

 causing a sound like a little coughing, while a Newt or fish was 

 being swallowed. The Blue Tit must therefore be as ignorant as 

 a cockney fowl, so far as the hissing of Snakes is concerned. 



The hissing of birds would therefore seem to be an inherited 

 expression of rage, derived from a very remote ancestry. 



With regard to butterflies perching in positions where they 

 are inconspicuous (Zool. 1899, p. 230), I have often observed 

 that the Common Blues are fond of sleeping not only on grass- 

 stems (as recorded by Mr. Cornish), but also on the dead and dry 

 seed-heads of plants, on which they are not noticeable. I have a 

 note of once finding quite a number of Blues (eight or nine ; the 

 MS. is not with me) sleeping at evening on one small dead 

 flower-head, which they would never have noticed in the sunny 

 hours of day. 



A Peacock Butterfly (Vanessa io) that lived one summer in a 

 garden where I was at Stroud, spent the day at one side of the 

 garden amongst the flowers, and at evening, or when the weather 

 darkened, it entered the shelter of an upper branch on the shady 

 side of a cypress tree on the other side of the garden, and amongst 

 the black stems the insect was wholly invisible. At other times 

 it never alighted on a cypress. The Peacock does not always 

 choose such a dormitory. I have generally found it prefer the 

 overhanging ledges of banks. The Red Admiral (V. atalanta) I 



Zool. 4th ser. vol. IV., January, 1900. d 



