CONTENTS. 



Page. 



Classification and synonomy 11 



Varieties 12 



Common names 12 



Geographical distribution 13 



Original home 14 



Food plants 17 



Status of boll worm in foreign countries 19 



Economic status in the United States 21 



Injury to corn 21 



Injury to cotton 23 



Injury to tomatoes 25 



Distribution and destructiveness in relation to life zones 25 



Transition zone 26 



Upper Austral zone 27 



Carolinian area 27 



Upper Sonoran area ' 28 



Lower Austral zone 28 



Austroriparian area ^ 28 



Lower Sonoran area 28 



The bollworm in the western United States 29 



Farm methods, in relation to bollworm injury 29 



Relation of weather to bollworm injury - 32 



Injury to cotton from other causes than the bollworm 35 



Earlier investigations of the Department of Agriculture 37 



Life history 40 



Summary 40 



The egg -- 41 



Description 41 



Oviposition 42 



Oviposition on corn 42 



Time and manner of oviposition 44 



Oviposition on cotton 45 



Time and manner of oviposition 45 



Distribution of eggs on cotton 46 



Oviposition on other plants 47 



Number of eggs laid by a single moth 48 



Deposition of infertile eggs ■ 49 



Eggs remaining in the ovaries at death 49 



Effect of fertilization on egg laying 49 



Changes in external appearance 50 



Embryonic development 50 



Hatching 50 



(5) 



