XXXVili INTRODUCTION. 
the potato, the very extensive cultivation of which 
vegetable root in the present day, will at once 
account for the far more frequent occurrence of 
this fine insect of late years than formerly. We 
are informed, by an able practical entomologist, 
that some of the fir-feeding Lepidoptera, (the French 
Sphinx pinastri and Geometra piniaria,) which 
formerly occurred in scarcely any other part of this 
island, save Scotland or the north of England, have 
of late years, since the growth of firs has been more 
extensively encouraged, been taken, one or both of 
them, in great abundance in the morenorthern parts.* 
The same law, or something analogous to it, holds 
good also in the vegetable world. Plants sometimes 
spring up, as it were spontaneously, or at least 
nobody knows how, as soon as the soil and situation 
are rendered suitable to their growth.” 
The field of Nature is of vast and ever boundless 
extent, and the objects which lie within it are ex- 
ceedingly numerous and diversified. To the mind, 
therefore, that has acquired a relish for cultivating a 
knowledge of natural objects, it never fails to prove 
an inexhaustible source of amusement. 
* See Hawortu’s Lepidoptera Brit, p. 278, 279. 
