14 
knot-grass that I discovered my missing ones. In their early stages 
these. caterpillars are sometimes green and then they sit on the 
leaves. Other groups of caterpillars are protected by their resem- 
blance to the bark of trees and to the lichens growing on them, 
while others again make their surroundings resemble themselves. 
The caterpillar ot the Large Emerald moth when it feeds 
-on the birch resembles a birch catkin; but it also occurs on the 
alder, and when young, before hibernation, is dull purplish all 
over; in this state it is like, in size and colour, the unexpanded 
bud of alder; after the alder shoots, and the caterpillar turns 
green, it cuts through the juicy stems of the shoots and gnaws 
‘them away for food, and then it looks like a young, partly-unfolding 
leaf projecting from the stem. Those of us wio have seen the 
brightly-coloured caterpillars of the privet and poplar moths might 
at first be inclined t» think they were conspicuous objects, but seen 
on their respective food plants the bright-coloured markings har- 
monize very beautifully with their surroundings. These ca erpillars, 
_just before they enter the chrysalis state, descend to the ground in 
order to bury init, and then their col ur changes to a dull purple, 
in harmony with the colour of the earth. The caterpillar of the 
Emperor moth (P. carpinz), which is nearly two inches in length, 
not only resembles the green colour of the heather upon which it 
feeds, but the small pinkish purple dots with which it is studded 
closely imitates the flower buds of the plants, and its habit of 
twining itself around the ste o when alarmed makes it almost im- 
possible at a little distance to distinguish it from the heather. 
Mr. Poulton (in Colours of Animals), gives the results of many 
experiments showing the power of caterpillars to adjust themselves 
to the colour of the leaf upon which they feed. ‘The next slide 
will show the larve of a continental nvctua (Catecala elocata) with 
the colour adjusted to that of the dar« twig; mixed with the food- 
lant. 
E Besides resemblance to their surroundings, and power to adapt 
their colouring t> the plants up >a which they feed, caterpillars are 
often brightly coloure l, and also possess curious appen lages which 
are used as warning colours and as a means of frightening their 
-enewies. As an instance of warning colours, I may mention thos: 
of the caterpillars of tle Magpie moth (Adraxa grossulariata) and 
Cinnabar moth (#. jacobe). Although the first named belongs to 
the ‘Stik’ family it makes 10 attempt to conceal itself, but all 
birds, lizards, frogs, ete. either refuse it altogether, or else express 
great disgust after tasting it. Thus its conspicuous colour warns 
its enemies that it is uneatable. Another means of defence is that 
of mimicing vertebrate animals. It is more common in tropical 
-regions than in our own country, but we have an instance of it in 
