THE EUROPEAN CORN BORER AND ITS CONTROL. 69 



EXPLANATION OF PLATES. 

 All except Figs. 12, 13 and 14 drawn from sketches by R. E. Snodgrass. 



Plate I. k>/^ 



Fig. 1. — First larval instar. 

 • Fig. 2. — Second larval instar. 



Fig. 3. — Prothoracic shield of first two instars. 



Fig. 4. — Third larval instar. 



Fig. 5. — Prothoracic shield of third instar; spines not shown. 



Fig. 6. — Fourth larval instar.' 



Fig. 7. — Prothoracic shield of fourth instar; spines not shown. 



Plate II 

 Fig. 8. — Fifth larval instar. 

 Fig. 9. — Prothoracic shield of fifth instar. 

 Fig. 10. — Sixth larval instar. 

 Fig. 11. — Prothoracic shield of sixth instar. 

 Fig. 12. — Venation of fore wing of adult. 

 Fig. 13. — Venation of hind wing of adult male. 

 Fig. 14. — Frenulum of hind wing of female. 



