OF INSECTS. 143 



parts more distinctly defined, and so much elongated, 

 that the whole digestive tube exceeds from six to 

 twelve times the length of the hody. The changes 

 which it undergoes in the progressive developments 

 of a Lepidopteron, (Pontia Brassicce, the common 

 cabbage-butterfly,) as traced by M. Herold,* are 

 principally the following : In the Caterpillar there 

 is a very short esophagus, with salivary vessels ap- 

 pended to it ; an extremely large cylindrical stomach, 

 and a short intestine, succeeded by a wide but short 

 caecum. Shortly after the chrysalis is formed, the 

 esophagus is found to have become longer and more 

 slender; the stomach to have decreased greatly, 

 both in length and diameter, while the intestine is 

 elongated, and the caecum terminates in a pretty 

 distinct rectum. As the chrysalis becomes older 

 farther changes ensue, and about eight days from 

 the time of its assuming that form, the sucking- 

 stomach can be discerned, and the stomach begins to 

 separate into two portions. These changes are more 

 sensible when the butterfly is on the point of being 

 disclosed, and after that event the esophagus is 

 very long and slender ; the sucking-stomach in the 

 shape of a large vesicle ; the stomach double ; and 

 the intestine very long and convoluted. Analogous 

 changes take place in many other tribes, into the 

 consideration of which we cannot now enter. 



To what has been said respecting the anatomical 

 features of the great alimentary organ, it may be ad- 



* Entwickelung-Geschichte der Schmetterlinge, &c. 1 roi 

 4 to. Cassei und Marburg, 1815. 



