38 INSECT MISCELLANIES. 



upon the sugar, in order to melt it, and thereby 

 render it fit to be sucked up, on precisely the same 

 principle that we moisten with saliva, in the process 

 of mastication, a mouthful of dry bread to fit it for 

 being swallowed the action of the jaws, by a beau- 

 tiful contrivance of Providence, pressing the moisture 

 along the channels at the time it is most wanted*. 

 Readers, who may be disposed to think the circum- 

 stance of the fly thus moistening a bit of sugar fan- 

 ciful, may readily verify the fact themselves, in the 

 way we have described. At the time when we made 

 this little experiment, we were not aware that several 

 naturalists of high authority had actually discovered, 

 by dissection, the vessels which supply the saliva in 

 more than one species of insect, as we shall now 

 describe. 



Swammerdam seems to have been the first to ob- 

 serve these in the small tortoiseshell butterfly (Vanessa 

 urticce) ; but as he could not trace their termination, 

 he says, with his usual scrupulous caution, " what 

 the office of these vessels is, and whether they may 

 not be the salivary ducts, I cannot take upon me to 

 determine t." Lyonnet afterwards discovered a con- 

 spicuous pair of these vessels in the caterpillar of the 

 goat-moth (Cossus ligniperdd), distinct from the silk 

 reservoirs*, with which Swammerdam, as well as 

 Ramdohr, was inclined to confound them ; an opinion 

 which Heroldt has also disproved in his admirable 

 anatomy of the cabbage caterpillar (Pontia brassicce). 

 The following are a few of the more interesting facts 

 given by Ramdohr, whose work we have studied with 

 much pleasure. 



The pipes which carry the saliva do not always 

 open into the mouth, but sometimes into the gullet, 



* J. R. f Book of Nature, part ii. page 21, 



| Traite Anatomique, page 112, 



