400 EXTERNAL ANATOMY OF INSECTS. 



stag-beetle {Lucanus Cervus), where the thorax receives 

 the head ; and very remarkably at the same point in the 

 Hercules-beetle (Dynast es Hercules MacLeay) : but be- 

 sides 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 con- 

 jecture, as I do not recollect ever to have seen any ex- 

 periments 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 ne- 

 gative state ? Every one knows that the fur of a cat has 

 electric properties, and there may be an important gene- 

 ral use of this kind attached to the fur and hairs of ani- 

 mals a . 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 b ; but this will apply only to 

 the hairs of larvae : 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. 



v. We are now to consider the composition of the in- 

 tegument; under which term I would include the diffe- 

 rent layers of which it consists, and its articulation. 



n Hair, in the Holy Scriptures, is used as the symbol of strength 

 or power. Judges xvi. 17 — . 1 Cor. xi. 10. 

 6 Anat. Compar. ii. 624. 



