360 



THE BIOLOGY OF INSECTS 



Fig. 80. — Stages in the paedogenetic development of Miastor ameri- 

 cana. a, early stage showing a few somatic cells {bm), a group of nutritive 

 cells (^0 and one "pole" primordial germ-cell (g) ; b, later stage with 

 two "pole" germ-cells {g), somatic cells {hn) toward edge of yolk; 



c, blastoderm {bm) enclosing yolk, and group of eight germ-cells {g) ; 



d, embryo with head-region (e), segmenting body, amnion {an) and 

 germ-cells {g) at hinder end. All highly magnified. After R. W. 

 Hegner {jfouni. Morph. xxv, 1914). 



