89 
many of the enemies of butterflies as on the mainland — at least 
there are decidedly much fewer lizards; still there are birds enough, 
and also different species of Mantids occur there, so one should 
expect to find specimens of the Thecla's showing molested wings. 
However, even if I can give no direct evidence, that the false 
head really helps to save the butterflies, when attacked, the ob- 
servations of Geo. H. Burn, published by Poulton!"), prove that 
it does so. He states that he has ,repeatedly come across fresh spe- 
cimens with that part of the hindwings injured, in many cases 
bitten completely out." Direct experiments would give the best 
proof; they could be carried out without much difficulty. 
There is, of course, one draw-back with this, otherwise so acute 
design — it does not work more than once, in case it is quite 
destroyed at the first attack. But then, anyhow, it has worked once, 
and that may be sufficient for the species, if not for the specimen 
in question. 
It is very interesting to see that these butterflies all behave as 
if they were perfectly conscious of the protection they enjoy. They 
do not fly restlessly as do so many other butterflies; they gene- 
rally flie only a little way at a time, and when they alight, they 
never seek to hide themselves. away, but on the contrary alight 
on very prominent places, where they are especially conspicuous. 
In two cases, however, there was found to be a special protective 
resemblance besides the device with the double head; one was 
entirely green on the underside of the wings and thus very hard 
to distinguish from the green leaves, another was brown on the 
underside of the wings, exactly like the dead leaves on the ground, 
on which it would rest. — It should be mentioned that in no 
Case did I observe any of these butterflies resting head downwards, 
but always horizontally on leaves or flowers. 
In all I observed at least a dozen different species of such 
double-headed butterflies, the more conspicuous of which are re- 
Presented in Pl. I. That the same remarkable habits will be found 
also in many other species of Thecla's with a similar structure of 
the hindwings, I cannot doubt. Some of the larger forms must be 
quite wonderful to see in nature. 
") Proceed. Entom. Soc. London. 1906. p- 15. 
