104 THE NATURE-STUDY OF PLANTS 
it again in the dark, and although I looked for it in 
the daylight on several occasions afterwards I never 
saw it again. Later on I fed a larva of the Small 
Yellow-underwing * for six days on the leaves of the 
Herb Robe.t and nothing else: at the end of that time 
it burrowed in the soil, and subsequently it pupated 
and hatched out quite normally: but I do not think 
it would have eaten these leaves from choice had I 
given it, for example, some of those of a Dock or a 
Primrose as well. 
Then there is the caterpillar of the Tiger Moth,t 
known as the Woolly-bear, a very omnivorous creature, 
to whom little indeed seems to come amiss. 
I kept one of them in captivity and supplied it 
with leaves ; it ate a very little two nights running, 
and then looked very unwell. It is often quite easy 
to know when a caterpillar is not up to the mark; 
it behaves differently, and this one lost the beautiful 
bright gloss of the long shaggy hairs that give it its 
popular name. 
I rather wondered what was the matter, especially 
as it got very restless, for it did not seem to me to be 
about to moult or to be full grown, so I gave it other 
food; nevertheless, after starving for another four 
days it spun its cocoon and turned into a chrysalis. 
I thought then that all was well, but I am sorry 
to say I have still got the chrysalis, for the moth which 
it contains never succeeded in forcing its way out as 
it ought to have done. 
I wondered without forming an opinion whether 
the diet of Herb Robert for two days had anything to 
do with its untimely death, and a second experiment 
leaves me in much the same state of mind, although 
* Triphena orbona. t Arctia caja. 
