DISPERSION OF GIPSY-MOTH LARViE BY THE WIND. 
17 
isolated infestations are scattered in hill and dale over 19,378 square 
miles of the New England States (PL VII), excepting Vermont, 1 and 
a comparison of such information with the foregoing data at once 
suggests the source of practically all spread of this species. 
OBSERVATIONS ON WIND DISPERSION AT SALISBURY BEACH, MASS., 
IN 1913 AND 1914. 
Salisbury Beach, owing to its separation by extensive marshes from 
infested woodlands and to the limited amount of favorable food plants 
for gipsy moths thereon, was selected as a desirable location to be 
cleaned up and watched for reinfestation. The south end of the 
beach (PL II), 1| miles in length, was scouted and the egg clusters 
were creosoted in 1913 and 1914. Beach plum was the predominant 
shrub growing on the sands and was not fed upon by the caterpillars. 
Bayberry, wild rose, willow sprouts, balsam poplar, and other small 
growth thrived to a certain extent and are favored food plants. 
The scouting in 1913 resulted in the finding of 144 egg clusters 
distributed over the beach in a few clumps of shrubbery. The con- 
trol work was followed up during the summer by frequent examina- 
tions for caterpillars, which resulted in their discovery in seven or 
more places other than where egg clusters were located. From 
one to six caterpillars were found in small isolated clumps of bay- 
berry and wild rose in no less than six spots near which there were no 
egg clusters. These patches of favorable food afforded good traps 
for the newly hatched caterpillars, which were being carried from the 
infested woodlands 1 mile to the west, as did the tanglefooted screen 
on which such large numbers were caught the same year. 
Seventy-seven egg clusters were found and creosoted in 1914 in the 
same area as was scouted in 1913. Thus it will be noted that there 
were slightly more than one-half the number of egg clusters found in 
1914 as in 1913, in spite of the rigid control measures practiced during 
the former year. The location of the beach with respect to the 
infested woodland across the marshes was ideal for heavy reinfesta- 
tion each year, and this condition prevails in apple orchards, wood- 
lands, and shade trees that are cleaned within the gipsy moth infested 
area and become reinfested annually by means of the wind. 
OBSERVATIONS ON ISOLATED TREES AND YOUNG APPLE ORCHARDS 
FOR REINFESTATION. 
Twelve isolated trees in the midst of cultivated fields and mowings 
were selected in the early spring of 1914 ; these were cleaned of egg 
clusters, trunks tanglefooted, and later examined for reinfestation b} r 
the wind. These trees were selected in towns about Merrimac, Mass. ; 
1 During the winter of 1914-15 a few small infestations were discovered in Vermont. 
