PLATE LIX 

 Toxoptera graminum: 



Fig. 1-3. — Sagittal sections. Embryo starting revolution. Note changing position 

 of the polar organ, shown at p. 0. X 83. 



Fig. 4-6. — Sagittal sections. Embryo making revolution. Note polar organ, shown 

 at p. 0., migrating backward. X 83. 



