594 ROBERT MATHESON 



out destroying or replacing them in any way whatever. Thus 

 he considers the epitheUum to pass over to the imago, though some- 

 what modified to adapt it to the changed conditions. As the 

 epithehum is sharply differentiated from the hypodermis he ex- 

 cludes any possibility of regeneration from imaginal buccal discs. 



Karawaiew ('99) in his studies on Anobium paniceum (Coleop- 

 tera) finds but slight changes in the fore-gut during metamor- 

 phosis. The imaginal epithelium develops directly from the 

 larval without any apparent changes. In this respect this beetle 

 exhibits much similarity to the ants. 



Angias ('00) finds in the bee and the wasp a well-marked zone 

 of growth between the fore- and mid-guts. He does not regard 

 this as an imaginal ring but more like the condition found by 

 Karawaiew in Lasius flavus. By the proliferation of the cells of 

 this growth area the greater part of the imaginal epithelium is 

 formed. The proliferating cells invade and engulf the larval 

 cells. The anterior part of the larval oesophagus becomes that 

 of the adult. He finds it difficult to distinguish the point of 

 union of the part formed by the cells from the growth zone and 

 that formed by the transformed larval epithelium. One passes 

 insensibly into the other. 



Deegener ('00) finds an imaginal ring present in the fore-gut 

 of Hydrophilus. During the prepupal period this imaginal ring 

 rapidly increases by mitotic divisions of the cells, while the larval 

 epithelium is discharged into the lumen where is found a consider- 

 able number of 'Kornchenkiigeln.' During the pupal period the 

 imaginal epithelium is formed into a cylindrical tube within which 

 are found remnants of the larval cells and Kornchenkiigeln. Later 

 Deegener ('04) finds he was in error regarding the presence of 

 Kornchenkiigeln within the lumen and he states that phagocytes 

 do not take any part in the breaking down of the larval epithe- 

 lium. 



Perez ('02) describes in Formica an imaginal ring for the fore- 

 gut, situated as in the Muscidae. During the prepupal period 

 the cells of this ring actively divide and the epithelium of the 

 oesophageal valve is discharged into the lumen. By the contin- 

 ued proliferation of the imaginal ring the fore-gut is elongated and 



