b CONTENTS. 
Remedial and preventive measures— Continued. Page. 
The ridge and coal-tar method r,<; 
Other barrier methods 68 
Necessity for preventing chinch bugs from becoming established in 
fields of wheal and grass 69 
Summary of remedial and preventive measures 72 
Probable origin and diffusion of the chinch hug 72 
Indications of a probable distant origin and later diffusion 74 
Unique appearance and gregarious habit 74 
Occurrence <>f the long and short winged forms and their distrilniti >n_ 7."i 
Relation <>f the inland and seacoast short-winged forms 7^ 
Probable course of diffusion 7^ 
Habits of the European species. Blissus doria Ferr_ 83 
Previous ideas on the diffusion of the chinch b lg s7 
Reasons for the present theory of diffusion 
Index 91 
