CONTENTS. 



Historical review of published writings on plant-bugs injurious to cotton bolls. . 11 



General considerations 13 



Nature of injury by plant-bugs 13 



Amount of damage to cotton by plant-bugs 20 



Plant-bugs as disseminators of plant diseases 23 



The conchuela (Pentatoma ligata Say) 23 



History 23 



Distribution 24 



Food plants ' 25 



Description 25 



• Life history 29 



Methods of study 29 



Adults 29 



Period between maturity of adults and beginning of egg laying. . . 29 



Reproduction 30 



Proportion of sexes 32 



Longevity '. 32 



Relation of temperature to activity of adults 35 



Eggs-..- 35 



Period of incubation 35 



Proportion hatching in the laboratory 37 



Effect of low temperature on vitality 38 



Hatching 38 



Nymphs 39 



Duration of nymphal stages 39 



Length of life without food 40 



Molting 41 



Habits : 41 



Nymphs 41 



Adults 43 



Fertilization 43 



Egg laying 43 



Feeding 44 



Gregariousness 47 



Flight 48 



Seasonal history 48 



Increase and decrease in numbers during the season 48 



Hibernation 53 



Destructiveness 55 



Individual capabilities 55 



Reduction in yield of infested cotton fields 57 



Effect of plant-bug attack on quality and market value of lint 61 



7 



