—_. 
18 
pillars will probably have tried ‘‘ beating,’ which consists of hold- 
ing a special apparatus something like an vmbrella under a tree, 
and then with a stout stick threshing the branches above it. On 
an examination of the contents afterwards, consisting of spiders, 
beetles, flies, and grub-looking caterpillars, it will be noticed there 
are what look like a number of twigs; presently, to the surprise 
of the novice, several of these ‘‘ twigs’ will raise themselves up, 
and begin to walk off as fast as their legs willcarry them. These 
are the caterpillars of different kinds of geometer moths. It is an 
extremely numerous family, nearly three hundred species being 
found in this country; but, until we beat them from their food 
plant, they are rarely seen, their great resemblance to their environ- 
ment helping their concealment. They possess only two pairs of 
claspers, while most other caterpillars have five pairs. These are 
placed at the posterior part of the body, which is long, thin and 
round, and stands out like a twig at an acute angle with the stem 
to which the claspers are tightly fixed. There are often little 
Lumps on the body which resemble buds or irregularities of the 
bark. In the day time the caterpillar is quite still, not moving 
until it needs food, which is generally taken at night. As the 
maintaining of this position for so considerable a time would 
cause great tension to the caterpillar, it spins a short thread. 
of silk, and attaches itself by this to the adjacent twig; in other 
ceses it fixes its lf in a fork of the branch, holding by both ends of 
the body. To complete the resemblance, the head of these cater- 
pillars is altered from the usual shape into one which suggests the’ 
end of a twig ‘In the caterpillar of the Small Emerald moth 
(Hemith-a thymiaria) there are two additional humps on the body- 
ring behind the head, and the latter is bent forwards and inwards, 
so that the end of the caterpillar is made up of four blunt 
projections forming perhaps the most suggestive resemblance to. 
the end of a twig.” (Colours of Animals, p. 29). Speaking of these 
protective resemblances, the late Mr. Jenner Weir says:—‘‘ After 
being thirty years an entomologist, I was deceived myself, and took 
out my pruning scissors to cut from a plum tree a spur which I 
thought I had overlooked. This turned out to be the larva of a 
geometer two inches long. I showed it to -everal members of my 
family and defined a spxce of four inches in which it was to be 
seen, but none of them could perceive that it was a caterpillar.” 
Last year I was rearing a brood of Aciva/ia arersata (the riband- 
wave moth) on knot-grass, and on several successive changes of 
food I noticed that they were gradually disappearing I then 
determined to count them, and on the next occasion I found I was. 
three or four short. I again carefully scanned the rejected food, 
but it was not until I passed my fingers down the stems of the. 
