FORE-GUT OF CORYDALIS CORNUTUS L. 597 



consists of tall cylindrical cells. These become much flattened 

 in the adult and there is consequently a great enlargement of 

 the lumen. 



Deegener ('08) investigated the metamorphosis of the intes- 

 tine of Malacosoma castrensis (Lepidoptera), which has a well 

 marked imaginal ring for the fore-gut. As in Cy bister he divides 

 the time of transformation into two distinct periods; — the shed- 

 ding of the larval intimaandthe formation of the pupal epithelium; 

 the shedding of the pupal intima and the formation of the imaginal 

 epithelium. The first period is completed at the end of the first 

 pupal day. The, pupal epithelium is identical with that of the 

 larva except for a slight transformation of the cellular contents. 

 He does not find any activity on the part of the imaginal ring, 

 although in its neighborhood there may be seen a few degenerating 

 nuclei during the pupal period. About the end of the third day 

 after pupation the pupal intima is molted and the formation of 

 the imaginal epithelium begins. This is completed between the 

 fifth and sixth days of the pupal life. The pupal epithelial cells, 

 except for a slight reduction in size and rearrangement of their 

 chromatin material, pass over directly into the imaginal epithe- 

 lium. 



It might be fui'ther noted here that Deegener considers the 

 basement membrane as a temporary structure, appearing only 

 while a well developed intima is lacking or to protect the epithe- 

 lium from the severe contractions of the surrounding muscles. 



Perez CIO) in his extensive studies on the metamorphosis of 

 the Muscidae confirms and extends the results of Kowalevsky 

 ('87) and Van Rees ('89) in regard to the post-embryonic develop- 

 ment of the fore-gut. 



THE EPITHELIUM IN CORYDALIS DURING METAMORPHOSIS 



The prepupal period 



The characteristics of the larval epithelium have been fully 

 discussed and illustrated in the first part of this paper. We shall 

 now examine the changes undergone during the prepupal period 

 up to the time of the last larval molt. The first changes appear 



JOURNAL OF MORPHOLOOY, VOL. 23,, NO. 4 



