PLATE 1 



EXPLANATION OF FIGURES 



All the figures are drawn with camera lucida. 

 Pieris rapae, L. 



1 A cross section of a silk-gland of a larva just hatched. X 250. 



2 A cross section of a silk-gland of a larva just hatched, a part of the cell. 

 X 1200. 



3 A cross section of a silk-gland of a little older larva. X 250. 



4 A cross section of a silk-gland of a little older larva, representing the 

 •condition after a moderate discharge of the secretion. X 250. 



5 A part of the gland-cell of a fairly grown larva. X 1200. 



70 



