LEAF-MINERS. 135 
the size of the body being quite a secondary considera- 
tion. In the present case, the larvae which we are 
supposed to examine belong to the lepidopterous order, 
in all of which insects the wings, when present at all, 
are of great comparative size. If, then, the full-grown 
larva is so small that it can lie concealed between the 
membranes of a leaf without causing any conspicuous 
alteration in its outline, it is evident that the perfect 
insect must be of almost microscopical minuteness. 
Accordingly, it has been found that the little moths 
which have been bred from such caterpillars are so small 
that they have almost escaped observation until com- 
paratively late years. 
How small these insects are may be imagined from the 
fact that many species of the Microlepidoptera, as they are 
fitly named, do not occupy, even with their wings spread, 
a space larger than is taken up by the capital letter at 
the beginning of this sentence. To “set” these tiny 
creatures is necessarily an extremely difficult task, and 
cannot be accomplished by the ordinary plan of running 
a pin through the thorax, and extending the wings on 
the “setting-board.” The only method of displaying 
them is to set them on white cardboard by means of 
gum, which is strengthened by many entomologists with 
various substances. A sheet of cardboard covered with 
specimens of Microlepidoptera neatly set is a very pretty 
sight, but needs the aid of the microscope before it can 
be perfectly seen. 
Even to the unaided eye, the tiny moths are seen to 
be beautifully decorated, their wings gleaming in favour- 
able lights like the throat of the humming-bird. But 
when placed under the microscope, especially, if it be 
furnished with a binocular tube, and illuminated by a 
suitable light, the wings are positively dazzling in their 
