EXTERNAL ANATOMY OF INSECTS. 399 
place, we may often observe a dense fringe or coating of 
the same substance. This you may see in the common 
stag-beetle (Lucanus Cervus), where the thorax receives 
the head ; and very remarkably at the same point in the 
Hercules-beetle (Dynastes Hercules): but besides these 
uses, there is probably one more universal, which will 
apply as well to those thinly scattered bristles and hairs, 
here and there one, to be noticed in many insects: but 
concerning this I can only throw out a conjecture, as I 
do not recollect ever to have seen any experiments with 
regard to this use of animal hairs. But may they not 
act as conductors, either to introduce some invisible fluid 
into the body in a positive state, or to convey it out, when 
received by other means, in a negative state? Every 
one knows that the fur of a cat has electric properties, 
and there may be an important general use of this kind 
attached to the fur and hairs of animals’. But, as I said, 
I give this as a mere conjecture; and only wish it may 
excite your attention to the subject, and put in exercise 
your natural tact for experiment. 
M. Cuvier regards the hairs of insects as merely a 
continuation of the epidermis, with which they fall when 
the animal changes its skin”; but this will apply only to 
the hairs of larvee: for the hairs of perfect insects in 
many cases are implanted in a pore, and pass through 
epidermis or crust to the membrane that lines it, in which 
they terminate. 
vy. We are now to consider the composition of the in- 
* Hair, in the Holy Scriptures, is used as the symbol of strength 
or power. Judges xvi. 17—. 1 Cor. xi. 10. 
b Anat. Compar. ii. 624. 
