6 
Life history — Continued. Page. 
The egg — Continued. 
Shrinking of infertile eggs 51 
Eating of shells and eggs by newly hatched larvae 51 
Percentage of eggs that hatch 52 
Length of the egg stage .• 52 
Effect of reduced temperatures 53 
Effect of atmospheric conditions 54 
Effect of submergence on eggs 54 
Eggs destroyed by storms 55 
Effect of sun on eggs 55 
The larva _. 55 
Descriptions of instars 57 
Possible causes of color variation 62 
Duration of larval instars 63 
Growth during the larval instars 64 
Influence of external conditions on growth 66 
Number of molts 67 
Process of molting 67 
Habits of neWly hatched larvae on cotton 68 
Effect of external conditions -on newly hatched larvae 68 
Character of injury 68 
Character of injury to corn .' 69 
Character of injury to cotton 69 
Character of injury to other plants 70 
Choice of food by larva^ 71 
Relative attractiveness of Upland and Egyptian cottons 71 
Comparative inj ury to early and late cotton 72 
Amount of damage done by a single larva 74 
Damage to young corn 74 
Damage to ears of corn 75 
Damage to cotton 76 
Number of larvae on a single plant 78 
Relation to the number of eggs laid 78 
Percentage of corn plants infested - 78 
Cannibalism 79 
Leaving the plant and entering the ground for pupation 80 
Formation of the pupal cell 81 
Variations in the form of the pupal cell 82 
Pupation in other situations 83 
Changes undergone in the formation of the pupa 83 
The pupa 84 
Description of pupa - 84 
Length of the pupal stage 84 
Effect of external conditions - 86 
Heat : --.. 87 
Soil 87 
Mortality during the pupal stage 88 
The adult 89 
Emergence 89 
Description of moth 89 
Size of moths - - 90 
Variation and possible causes - 90 
Anatomv and sexual differences 91 
