72 
INTRODUCTION TO 
against cold and other atmospheric influences, con- 
sists of a coating of varnish, hair or down stripped 
from the body of the insect, leaves drawn carefully 
around them, or a covering of frothy matter. The 
female coccus converts her whole body into a cover- 
ing for her eggs, enveloping them closely on every 
side ; the great water-beetle ( Hydrophilus piceus) 
deposits them in a bag, and carries them at the ex- 
tremity of her abdomen, like the spider commonly 
observed under stones, [by com saccata.) In form, 
colour, sculpture, &c., they vary infinitely in different 
tribes ; some of them we have already described and 
figured, and it will he more satisfactory to notice 
the peculiarities of others in connection with the par- 
ticular history of the insects that produce them, than 
to introduce here a lengthened general account of 
objects so dissimilar. 
The number of eggs laid by different species, is as 
various as their properties. At one extremity of the 
scale they approach the vertehrated races, at the other 
they surpass all other animals in the creation. Thus 
a pretty large fly, which may frequently he observed 
resting on the stems of trees, ( Mesembrina meridiana) 
lays only two eggs, while the female white ant lays 
probably not fewer than forty or fifty millions in a 
year, extruding them, when in the act, at the rate of 
sixty in a minute ! Of such as are intermediate be- 
tween these two extremes, the numbers are, of course, 
very various ; hut it may he affirmed that insects are 
in general much less prolific than fishes. Among 
the latter, a million occurs occasionally, and half that 
