OF OUR LEPIDOPTEROUS INSECTS. 
59 
to find one anywhere. I have occasionally taken this moth on the 
Downs at Aldbury. 
Another method of concealment is to sit upon some surface the 
colour of which resembles that of the moth’s upper wings. One 
morning, two or three years ago, I saw four of the large red under¬ 
wings sitting upon an oak fence at Watford. The grey colour of 
their upper wings is extraordinarily like that of a fence which has 
become weather-stained. The brilliant under wings are, of course, 
entirely hidden when the moth is at rest. I called a young friend 
of mine, who happened to he near, and asked him to examine 
the fence and see if he could find a moth sitting upon it. After 
walking slowly along it and looking over it carefully, he confessed 
that he could not. When I told him there were four, and showed 
him the size of them, he was not a little astonished. 
The fourth group, the Geometrae, or Geometers as they are 
commonly called, are very different from the last. They have thin 
bodies, even the thorax is small, and they are furnished with much 
more ample wings, which they can either raise vertically over their 
hacks, as butterflies do, or lay flat as other moths do. 
The wings are thin, and can he laid so close to whatever the 
moth is sitting upon that when some of the darker species rest in 
this way upon a tree trunk or a fence, it is often very hard indeed 
to see them. The markings of the wings of many of them are 
curiously like moss or lichen, and they are very clever at finding 
a surface coloured like themselves to rest upon. 
The larvae of the Geometrae differ very much from the typical 
form. They have the usual thirteen segments, and the six true legs 
on the 2nd, 3rd, and 4th. But as a rule they are without the first 
three pairs of prolegs, having only four instead of ten. Their 
method of progression is therefore by making a series of loops; 
they bring the prolegs close up to the true legs, then holding by 
them the larva stretches itself out to its full length, holds by its 
true legs, and again draws its prolegs forward. Prom this method 
of proceeding they are called Loopers or Geometers, because they 
seem to measure the earth as they go. They have also a peculiar 
attitude when at rest: they hold to a branch, generally a small 
one, of the tree or shrub upon which they feed, and then stretch 
themselves at full length at an angle from the branch. In this 
position their resemblance to a twig is marvellous, and it needs 
a sharp eye, even with a knowledge of this habit, to find them. 
Many of the larvae have a spinneret beneath the mouth, from 
which a fine silk is produced, and they are often seen hanging 
from trees by their silken web. 
The Geometrae are an extensive group, hut they are not usually 
to he attracted by sugar or other sweets ; some of them will 
occasionally come to sugar, but they must as a rule be taken flying 
at dusk. The majority of them hybernate as pupae, which are 
generally on the surface of the ground or spun-up on trees. 
Most of the Thorns pass the Winter in the egg state. Very few 
hybernate as larvae, and with them the dormant condition is only 
