208 NATURAL HISTORY OF WASPS. 
alter the style of the nest. A permanent altera- 
tion of the climate, such as the insects could not 
adequately temper for themselves, would probably 
destroy the local species, and cause the naturalization 
of others from foreign countries. But though a 
change of seasons and climate might bring the 
Chartergus, for instance, here with her card-board 
nest, there is no reason to think that any such cli- 
matic changes would induce the British wasps to 
build card houses. 
One thing more British wasps’ nests have m com- 
mon, namely, the end of all their labour, the wreck and 
ruin of their wonderful fabric. Where no accident 
has interfered with its growth, or brought it to an 
untimely end, the limits to the size of a nest are 
prescribed by physical and physiological laws. The 
latter class, to which we shall return farther on, are 
probably the most important, but certain physical 
considerations lead to the.conclusion that a paper 
structure of this nature cannot grow very large. In 
the species which use a more textile material, the 
constantly increasing deviation of the marginal cells 
from the normal vertical direction has probably 
something to do with limiting the lateral growth of 
the comb. And where the more friable nature of the 
materials excludes this particular limitation, com- 
pelling the cells to be built straight and parallel 
throughout, im this very circumstance we have 
another not less important influence at work, re- 
stricting to a few inches the diameter of a comb 
which could have any reasonable chance of holding 
together. And so, too, with regard to the number 
