196 INTERNAL ANATOMY OF INSECTS. 
without the flea appearing alarmed 3 . Many caterpillars 
are accustomed to extend their bodies from a twig, sup- 
ported merely by the four hind feet, in one fixed attitude, 
either in an oblique, horizontal, or vertical direction, 
either upwards or downwards, and that for hours to- 
gether. We may conceive what prodigious muscular 
force must be exerted upon this occasion, by reflecting 
that the most expert rope-dancer, though endued with 
the power of grasping with his feet like a bird with its 
claws, could not maintain himself in a horizontal position 
even for an instant. Bradley asserts that he has seen a 
stag-beetle carry a wand half a yard long and half an 
inch thick, and fly with it several yards b . Some insects 
have the faculty of resisting pressure in a wonderful de- 
gree. If you take a common dung-chafer (Geotrnpes) 
in your hand and press it with all your strength, you 
will find with what wonderful force it resists you ; and 
that you can scarcely overcome the counteraction, and 
retain the insect in your hand: was it not for this quality, 
the grub of the gad-fly must be crushed probably in 
passing through the anal sphincter of the horse c . But 
that of Eristalis tenax affords a more surprising instance 
of this power of counteraction: — an inhabitant of muddy 
pools, it has occasionally been taken up with the water 
used in paper-making, and strange to say, according to 
Linne, has resisted without injury the immense pressure 
given to the surrounding pulp d ; like leather-coat Jack 
mentioned by Mr. Bell", who, from a similar force of 
3 N. Diet. d'Hist. Nat. xxviii. 249. 
h Phil. Ace. of Works of Nat. 144. 
c Clark in Linn. Trans, iii. 309. d Fn. Succ. 1799. 
e Anatomy of Expression in Painting, 1 70. 
