xxiv LIST OF ILLUSTRATIONS 



ITG. PAGE 



16. Average length of the crop-growing season in days (U. S. 



Weather Bureau) . . . .78 



17. Interior view of a one-seed drop cotton planter (B. F. 



Avery & Sons Plow Co.) . . Ill 



18. Adult boll-weevil showing characteristic teeth on front legs 



which serve to distinguish this insect from other 

 weevils (Paddock) . ... 127 



19. Showing variation in size of boll-weevils (Paddock) . 128 



20. Root distribution of corn at silking time (TJ. S. Dept. 



Agr.) . . : 152 



21. Structure of corn plant at different stages of growth 



(after Bull) .. . . 155 



22. Ear of com showing tendency to laminate (after Harsh- 



berger) 158 



23. Botanical parts of the com kernel and its integuments 



(after Harshberger) 159 



24. Cross section of the outer portion of a grain of corn (after 



Webber) . .160 



25. Illustrating development of corn stem (after Montgomery) . 167 



26. Illustrating the process of fertilization of the corn flower 



(after Montgomery) .. . 169 



27. Illustrating structure of com kernel at pollination (after , 



Crosthwait) . . . 170 



28. Cross-section of com ear looking toward the base (after 



Winton) . . . . 171 



29. Illustrating the relationship between gama grass, teosinte, ■ 



and corn (after Montgomery) . 175 



30. A small ear of the pod-corn group r 178 



31. An ear of white rice pop corn (U. S. Dept. Agr.) ' . 178 



32. An ear of White Pearl pop corn (U. S. Dept. Agr.) . 179 



33. A good ear of the flint-corn group (U. S. Dept. Agr.) 180 



34. A good ear of dent com (TJ. S. Dept. Agr.) . . 181 



35. An ear of the sweet-corn group . . 182 



36. Showing the average angle of declination of corn ears after 



five generations of breeding for erect ears (III. Sta- 

 tion) ... 188 



37. Showing the average angle of declination of corn ears after 



five generations of breeding for declining ears (111. 

 Statio-n) . . . .189 



