CONTENTS. 
Page. 
Introduction 7 
Means by which insects are spread 7 
Investigations of the dispersion of the gipsy moth 8 
Control work abandoned. 9 
Gipsy-moth work resumed. 10 
The automobile as a means of dispersing the gipsy moth 11 
Other means of dispersing the gipsy moth 11 
Relation of birds to the dispersion of the gipsy moth : 12 
Continued dispersion of the species unexplained 15 
Suggestions concerning the spread of larvae by the wind 16 
Experimental work 16 
Experiments at Lincoln, Mass 17 
Experiments in Lynn Woods, Mass 18 
Experiments at Cliftondale, Mass 19 
Experiments on Lynn Marshes, Mass 20 
Quantity of silk produced by first-stage gipsy-moth larvae 23 
Relation of temperature to hatching of eggs 24 
Effect of temperature on activity of larvae 25 
Laboratory experiments 27 
Field observations 28 
Relation of activity to the spinning of silk. 28 
Locations where egg clusters are deposited. 28 
Distance first-stage larvae can crawl 29 
Degree of infestation 30 
Kinds of food plants '. 30 
Condition of food plants .' 31 
Direction and velocity of the wind 31 
General summary 41 
General conclusions 41 
Relation of scouting records to wind dispersion 42 
Records of dispersion of the gipsy moth secured from reports of scouting in 
several selected cities 42 
Records of dispersion secured from several selected towns 45 
Plans for scouting woodland areas 50 
Record of scouting in Lisbon, Me 51 
Record of scouting in Yarmouth, Me 53 
Record of scouting in Milton, N . H 53 
Record of scouting in Tilton, N . H 54 
Record of scouting in Bennington, N . H 54 
Record of scouting in Gardner, Mass. 55 
Record of scouting in Grafton, Mass 56 
Record of scouting in Wareham, Mass 57 
Results of scouting woodland areas 58 
Effect of wind spread on the problem of gipsy-moth control 60 
Summary 60 
Recommendations 61 
5 
