core. In the same way the plu~ or colls is formed, 

 by the hollowing out of ths solid archenteros.. 



Besido their ragged outline- the walls of ths 

 larva!- have another peculiarity in their structure, 

 forjudging by the number and position of the nuclei, 

 they are from two to thro-:- colls in thickness ,E!ig. 3. 



Cell walls arc- not to be mod: out in any stags 

 of development . 



