90 Queries and Answers* 



Art. II. Queries and Answers. 



The Preservation of dead Insects. — Sir, Your correspond- 

 ent M. P. affirms (Vol. V. p. 746.) that " it is impossible to 

 apply the solution to every part of the inside of most insects." 

 I beg permission to remind him, that there is no fighting 

 against impossibilities ; and that, where his assertion holds 

 good, the case is hopeless. With regard to his observation, 

 that he has found " the solution cannot be applied to the out- 

 side of most insects (especially Libellulae), without, in course 

 of time, injuring their colours," I request his attention to the 

 few following observations : — There are two grand distinctions 

 to be made in the colours of insects. Those colours which 

 originate from without, as in the moths and butterflies, remain 

 unimpaired in pristine splendour after death, until they are 

 destroyed by force or by accident. On the other hand, those 

 colours which have their source from within, and proceed 

 from moist substances, gradually fade after the death of the 

 insect ; and, in some cases, even totally disappear, when the 

 substances from which they drew their origin have become 

 dry and hard. By long experience, I know that the colours of 

 insects which are produced internally, as in the red dragon fly 

 of Guiana, cannot be made permanently any process, after the 

 death of the insect; but those colours can be renewed with great 

 and durable effect. Suppose your correspondent were to take 

 an English dragon fly (which, I must inform him, I have never 

 dissected), and sever the head from the thorax, the thorax 

 from the abdomen, and then subdivide the abdomen at every 

 third ring : this would enable him to clear away all the moist 

 internal parts, from whence the colours draw their source. 

 A nearly transparent shell would remain ; and he would only 

 have to introduce into it colours similar to those which the 

 insect exhibited in life, after having washed it well with the 

 solution. The joining again of the dissected parts would 

 complete the process. All this appears difficult : still it may 

 be effected. I have read somewhere of a Frenchman who 

 could harness a flea : I, myself, have dissected the Cayenne 

 grasshopper, and renewed its colours with great success. In 

 1808, after dissecting the bill of the toucan, I completely suc- 

 ceeded in renewing the blue, which had been removed by the 

 knife ; and, I believe, the specimen which I produced was the 

 first ever exhibited, in its renewed colours, since the discovery 

 of America. Should your correspondent ever stumble on the 

 Wanderings^ he will see a full account of this. 



As to the decay to which your correspondent alludes, I am 

 at a loss to know what to say on the subject ; because, where 



