280 THE INSECT WORLD. 
carries it to the end of the tube, against which it attaches it. It 
repeats many times in succession a similar manceuvre, sometimes 
coming partly out of its tube, and then again re-entering it to fix 
against one of its sides a new piece of wool.” 
After having worked for about a minute at one end of its tube, 
it thinks of lengthening the other. It turns itself round in its 
tube with such quickness, that you. would imagine it could not 
have had time to do so, and would think that its tail was formed 
in the same way as its head, and possessed the same address in 
choosing and tearing out the bits of wool. 
Furthermore, when the moth 
which is working at elongating its 
case does not find the threads or 
hairs of wool to its taste within 
reach of its head, it changes its 
place. Réaumur saw this insect walking, at some speed even, car- 
rying with it its case. It walks on its six front legs (Fig. 295). 
With the middle and hind legs it clings to the interior of its case. 
At the same time that the larva becomes longer it becomes 
stouter. Very soon its garment will be too narrow for it. Will 
it enlarge its old coat, or will it make itself a new one? Réaumur 
discovered that it preferred to widen its old coat. 
This is what our naturalist saw when he placed larvee with blue 
cases, for instance, upon stuff of a red colour. The bands, which 
extended in straight lines from one end of the case to the other, . 
showed the part that had been added. 
“From watching them at different times,” says this admirable 
observer, “I find that the means which they employ is precisely 
that to which we should have had recourse in a similar case. We 
know of no other way of widening a sheath, a case of any stuff 
that we find too narrow, than to split it right wp and to let in a 
piece of the proper size between the parts which we have thus 
divided ; we should let in a piece on each side if the shape of the 
tube seemed to require it. This is also exactly what our larve do, 
with an extra, and which with them is a necessary, precaution, so 
as not to remain exposed whilst they are working at the enlarge- 
ment of their garment. Instead of two pieces, which should each 
be as long as their case, they let in four, each of which is not longer 





Fig. 295.—Larva of a Tinea walking. 
