CHAPTER V. 
ASSOCIATIONS AND MIGRATIONS OF LEPIDOPTEROUS 
INSECTS. 
In quadrupeds, birds, and fishes, there are in- 
stances of extraordinary periodical migrations, prin- 
cipally for the purpose of obtaining food in more 
abundance, when it becomes scarce, from the effects 
of climate or other circumstances. In insects, too, 
there are frequent extensive migrations, to account 
for which we find some difficulty. It is easy to see 
the reason why some species of caterpillars associate, 
as they, for their mutual protection, construct nests 
wherein to retire, both during night and in bad 
weather. The Papilio Jo and cinixia are examples 
of this: the former constructs a nest like the Proces- 
sionary Moth, although differing in some particulars. 
Some insects associate only in their imago state ; 
while others are gregarious in both conditions. 
Others, again, congregate while in their larvee form ; 
which, with a very few exceptions, is the case with 
the numerous tribe of lepidopterous insects. These 
are hatched together, and remain in compact, for 
