198 INSECT TRANSFORMATIONS. 



v^ry extraordinary accuracy, enumerates nearly 2000 

 species of native moths and butterflies; and as the 

 females of tiiese are for the most part very prolific, we 

 have little reason to be surprised at the occasional 

 extent of their depredations. The 2000 species just 

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

 native insects, most of the g'rubs and mag-g'ots of 

 which are exceedingly 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 dig-estion. A cater- 

 pillar will, as we have seen, devour in a month 

 60,090 times its own weight of leaves, while the 

 moth or the butterfly into which it is afterv/ards trans- 

 formed may not sip a thousandth part of its weight 

 of honey during its whole existence. Now, in the 

 caterpillar. Nature has provided 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 cater- 

 pillar 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 diminished, 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 con- 

 tracted 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 



I 



