400 INSECT TRANSFORMATIONS. 



having deposit her eggs on a plant of the buckthorn 

 {Bhamnvs Jrangula), which we had placed in a 

 garden-pot for this purpose ; and we remarked that 

 she manifested no inclination to move from the same 

 leaf, except for an hour or two in the forenoon, and, 

 when it was damp or cloudy, not even then. If 

 disturbed in her repose, she would fall down as if 

 lifeless, and continue her sleep — (if sleep it was), 

 without being awakened by the fall, till her regular 

 period of animation returned. 



We have used the qualifying phrase — ** if sleep it 

 was ;" because the rest of insects, though correspond- 

 ing, in the circumstance of remaining without motion, 

 with the sleep of the larger animals, may not agree 

 in any other respect, — and particularly in the 

 quiescence of the senses. In the important point of 

 the state of the brain, it does not appear how there 

 could be any agreement in the phenomenon ; as may 

 be inferred from comparing the structure of insects, 

 as respects their nerves and blood-vessels, with that 

 of man. 



Insects, though possessed of nerves, have nothing 

 similar to our brain and spinal cord, the two sources 

 of our nerves of feeling and of motion, as so beauti- 

 fully explained by the recent discoveries of Mr. Charles 

 Bell. Instead of this, they have a chain of what are 

 called ganglia, or bundles of nervous substance, and 

 from each of these bundles nerves branch out to the 

 parts contiguous, — each ganglion forming the centre 

 of feeling to the parts to which its nerves run ; and 

 hence it is that insects will live, and (so far as we 

 can perceive) feel comparatively little general pain 

 and inconvenience from the loss of their limbs or 

 even of their heads. Thus the tail of a wasp or a 

 bee will sting long after it is severed from the body, 

 and the head of a dragon-fly will eat as voraciously 

 after it is cut oflf, as if it had to supply an insatiable 



