LEPIDOPTERA. 271 
= 
end of one of these leaves has, it appears, been rolled back towards 
the interior surface, in order to describe the first turn of a spiral, 
which is then-covered by many other turns (Fig. 282). Some 





Fig. 282 —Oak leaf rolled perpendicularly. Fig. 283.— Oak leaf rolled sideways. 
leaves are rolled towards their exterior surfaces, others are rolled 
towards their interior surfaces, but in a totally different direction. 
The length or axis of the first roll is perpendicular to the principal 
rib and to the stalk of the leaf, the axis of the latter parallel to the 
same rib (Fig. 283). Work of this kind would not be very difficult 
to perform for those who had fingers; but caterpillars have neither 
fingers nor anything equivalent to fingers. Moreover, to have 
rolled the leaves is only to have done half the work: they must be 
retained in a position from which their natural spring tends con- 
stantly to draw them. The mechanism to which the caterpillars 
have recourse for this second part of their work is easily perceived. 
We see packets of threads attached by one end to the surface of 
the roll, and by the other to the flat surface of the leaf. They are 
so many bands, so many little cords which hold out against the 
spring of the leaf. There are sometimes more than from ten to 
twelve of these bands arranged nearly in the self-same straight 
line. Lach band is a packet of threads of white silk, pressed one 
against the other, and yet we must remember all are separate.’’* 
Réaumur made the oak-leaf rollers work in his house. He has 
* Mémoires pour servir 4 1’ Histoire des Insectes, tome ii., page 210 (5e Mémoire). 
