EECOMMENDATIONS. 61 
By far the greatest dispersion is due to the fact that first-stage 
caterpillars are blown by the wind. A glance at the present infested 
territory shows that dispersion has been along the line of the prevail- 
ing winds immediately following the hatching of the caterpillars. 
One condition favoring wind spread is the presence of large woodland 
colonies which are overpopulated with caterpillars. This stimulates 
activity on the part of the insects in search of food and affords oppor- 
tunities for them to be carried away by the wind. High temperature 
increases the activity of the caterpillars, and this tends to increase the 
chances of their being blown away. Weather records for the past 10 
years show that the prevailing winds during April and May, when the 
temperature is high enough to make the caterpillars sufficiently active, 
and when the wind is strong enough to blow them 'for any great 
distance, are for the most part from the south and southwest. 
The character of the food has a very important bearing on' the 
dispersion of this insect, because unless caterpillars that are blown 
by the wind are able to find lodgment on favorable plants they will 
not survive, and there will be no opportunity for the species to become 
established. If a number of first-stage caterpillars were dropped by 
the wind into a forest of solid pine they would not be able to establish 
a colony, because these small caterpillars can not survive on pine 
foliage. There are other trees, particularly conifers, which are 
equally immune from injury by the first-stage caterpillars, and upon 
which they are not able to develop. This shows that large blocks of 
unfavorable food plants will not only prevent the establishment of 
the insect, but that such woodland will require no treatment what- 
ever, provided it is isolated by removing the favored food plants 
near by. 
RECOMMENDATIONS. 
As a result of the experiments which have been conducted and a 
study of the data which have been secured, the following recommenda- 
tions are made, as these have a practical bearing on the gipsy-moth 
problem : 
(1) National legislation should be enacted to provide for the 
inspection of lumber products or other material which is likely to 
carry the gipsy moth from the territory which is now infested to 
uninfested regions. This is particularly important and is distinctly 
of national concern, because goods of this sort are often shipped to 
far distant points in the United States, and without careful scrutiny 
excellent opportunities are offered for establishing new colonies 
remote from the area in New England which is now infested. 
(2) Inasmuch as certain coniferous trees, if grown in solid stands, 
will not furnish favorable food for small gipsy-moth caterpillars 
that might be distributed by wind spread, and as some of our decidu- 
