178 CATERPILLARS. 
view to the detection of their presence; and, although this may seem at 
first sight a very hopeless method of proceeding, it is remarkable how 
much success may attend it if pursued systematically and perseveringly. 
Two points, if borne constantly in mind, will help the collector greatly, 
and they are these :—First, that it is impossible for a caterpillar to live 
tipon a plant without leaving some traces of its presence; and second, 
that we may generally expect to find in the outward appearance and 
colouring of the caterpillar some resemblance to that of the objéct upon 
which it rests. The great thing, then, in finding caterpillars is to 
educate the eye to discern the distinctions which exist between them 
and the objects on which they feed; and this sometimes is no easy 
matter. Some caterpillars resemble so closely pieces of stick, leaf-buds, 
&c., that it is almost impossible to detect them by any method short of 
actual touching. And the habits of many render them almost equally 
difficult of discovery. As a rule, caterpillars feed almost entirely by 
night ; and during the day they rest either upon some patt of the food- 
plant, or upon some object near to it. The best time for searching, then, 
js unquestionably at night—or, perhaps, to speak more accurately, in the 
dusk of the evening. At this time, aided by a lantern, we may some- 
times take in favourable situations many species which are not otherwise 
easily to be procured, especially among the Noctuw#. And, indeed, it 
may be taken as a general rule that the caterpillars of this family are 
rarely to be taken during the day. Like the perfect insects into which 
they develop, they prefer the darkness and security of night; and if we 
wish to obtain them it is by night that we shall meet with the greatest 
measure of success. Some of even these, however, may be sought for 
during the day in their retreats. For example, the caterpillars of 
Orthosia Upsilon may be found sometimes in great abundance under 
loose pieces of bark on willow trees at the beginning of May, while 
Cirrhedia xerampclina, a decided rarity, is to be met with about the 
same time among the loose rubbish and grass at the roots of ash trees. 
Not a few caterpillars are likewise to be found—at least, so it is said— 
during the early months of the year among the dead leaves, which may 
be gathered into a large bag and breught home to be examined at our 
leisure. The majority of the caterpillars, however, which we find during 
the day-time, belong either to the order of Bombyces or to that of the 
Geometre. The former of these are not difficult to discover, being 
generally hairy, often brightly coloured, and feediag in much more 
exposed positions than do other caterpillars. It is as well, however, to 
be cautious about touching them, as the hairs often come off, and in 
some cases—as, e.g., Liparis chrysorrhwa—possess irritating properties 
which produce painful swellings on the hands. The caterpillars of the 
Geometre, on the other hand, are destitute of hairs and perfectly 
harmless; they lie during the day closely pressed to the mid-rib of a 
leaf, or the branch of a tree, the green species usually choosing the 
former situation, while those of a brown or buff tint prefer the latter. 
The best way to find them in such situations is to get underneath the 
tree and look up through the leaves against the sky, when the cater- 
pillars will frequently be seen. Some of them, however, as well as some 
