VORACITY OF CATERPILLARS. 365 



flies ; and as the females of these are for the most part very- 

 prolific, we have little reason to be surprised at the occa- 

 sional extent of their depredations. The 2000 species just 

 mentioned are, besides, not more than a fifth of our native 

 insects, most of the grubs and maggots of which are exceed- 

 ingly voracious and destructive. 



It appears to be indispensable for most insects to feed 

 copiously during their larva state, in order to supply a 

 store of nutriment for their subsequent changes ; for many 

 of them eat nothing, and most of them little, after they 

 have been transformed into pupae and perfect insects. 

 What is no less wonderful, a corresponding change takes 

 place in the internal formation of their organs of digestion. 

 A caterpillar will, as we have seen, devour in a month 

 60,000 times its own weight of leaves, while the moth, or 

 the butterfly, into which it is afterwards transformed, may 

 not sip a thousandth part of its weight of honey during its 

 whole existence. Now, in the caterpillar, nature has pro- 

 vided a most capacious stomach, which, indeed, fills a very 

 large portion of its body ; but in the butterfly the stomach 

 is diminished to a thread. By a series of minute dissections, 

 conducted with great skill, Heroldt traced these changes, 

 as they successively occur, from the caterpillar to the 

 butterfly. In the caterpillar he found the gullet, the honey- 

 stomach, the true stomach, and the intestines capacious. 

 Two days after its first change all these are visibly dimi- 

 nished, as well as the silk reservoirs, which, in a chrysalis 

 eight days old, have wholly disappeared ; while the base of 

 the gullet is dilated into a crop, and the stomach still more 

 contracted into a spindle form. When near its change into 

 the perfect insect the gullet is still more drawn out, while 

 the crop, still small, is now on one side of the gullet ; and 

 ■ in the butterfly is enlarged into a honey-stomach. 



It is remarkable that in men of such extraordinary ap- 

 petite as amounts to a disease {Bulimia, CuLLEN),the natural 

 capacity of the stomach, which, according to Blumenbach, 

 contains about three pints,* is very much enlarged. This 



* Bkimenbach, Phytiiol., s. xxiii. 



