266 | THE INSECT WORLD. 
This packet is more or less large according as the height ascended 
by the caterpillar is greater or less. All the turns of the thread 
which compose it are entangled. So the caterpillar does not con- 
sider it of any value; as soon as it can walk it gets rid of it, sets 
its legs free, and leaves it behind before it has taken one or at 
most two steps. Hach time, then, costs it the cord it made use of 
to effect its ascent, but this is an expense it can always be at when- 
ever it likes; it has in itself the source of the matter necessary 
for the composition of the thread, 
and it 1s a source in which that 
which was drawn off is being con- 
tinually re-supplied. Moreover, 
spinning the thread costs the 
caterpillars little; indeed, the 
loopers economise this thread so 
little that most of them leave it 
behind them wherever they go.” 














They are found on many trees, 
but particularly on the oak, whose 
foliage they often entirely devour. 
They burrow into the ground to change into chrysalides, and 
undergo all their metamorphoses in the course of the year. Others 
do not become perfect insects till the autumn, or sometimes not 
even till the following spring. A few assume the perfect state in 
winter. There are, indeed some of these, such as the males of thé 
Hybernias, which fly about on the foggy evenings of November. 
The females of this genus have either no wings at all, or else only 
rudimentary ones. Two species, the Hybernia defoliaria, or Winter 
Fig. 262.—Hybernia leucophearia, male. 

Fig. 263.—Winter Moth ( Hybernia Fig. 264.—Winter Moth ( Hylernia 
defoliaria), male. defolaria), female. 
Moth, and the Chimatobia brumata, abundant here, are very 
common in the environs of Paris. 
