SPOTTED ELEPHANT HAWK-MOTH. 151 
more adyanced, they become so conspicuous that 
their numbers are reduced by marine birds that 
feed upon them. Sometimes they may be traced 
by their soil, at other times they may be seen far 
from the spot where they fed, at the extremity of a 
tall rush. They are full gro^vn about the middle of 
September, when they descend into the sand and 
change into chrysalides, forming a loose case of 
earth around them, from which they emerge the 
beginning of the following June. Sometimes, how- 
ever, they remain in the pupa state two seasons, as 
many other Lepidoptera do ; — a wise provision of 
Nature to prevent any accident from destroying the 
whole brood. The sand-hills where the larva is 
found are of great extent and magnitude, and must 
have been collected by the winds and storms to 
which they are constantly ' exposed : during the 
winter the whole soil is frequently removed, so as 
completely to alter the surface of the country ; a 
great number of the pupa must consequently be 
destroyed or buried at a great depth below the 
surface, where probably they lie hid until they are 
brought to light and life by the influence of the 
elements*.’’ 
* Curtis’ British Ent. i. p. 3. 
