18 
BULLETIN 273, U. S. DEPARTMENT OF AGRICULTURE. 
where there was a general infestation. Some of them were later dis- 
carded owing to the discovery of overlooked egg clusters that had 
hatched. On the trees retained there were from 2 to 8 and in one 
case 11 large caterpillars above and below the tanglefoot, indicating 
that there was reinfestation by the wind. The top of a medium to 
large sized apple tree would offer more resistance to the wind than 
did the screen on the Merrimac standpipe, upon which was lodged 
approximately one first-stage caterpillar to every square foot of wire 
exposed. 
Some further observations confrrming these conclusions were made 
by Mr. C. E. Hood in July, 1914, in two young apple orchards in 
Merrimac (PI. VI) and West Newbury, Mass. These orchards were 
2 and 4 years old, respectively, and clean cultivation was practiced 
in them. A large number of the trees were examined in the center 
of these orchards, which were in some cases 500 yards from the 
nearest infestations on larger trees. Thirty-four large larva? were 
foimd in selected areas of the two orchards, not more than one of 
which appeared on a single tree. Xo egg clusters could be found, 
and it was concluded that the infestation was due to windspread. 
'Mr. J. V, Schaffner, jr., has also reported a similar incident from 
Dover, Mass. 
SMALL LARVAE BLOWN INTO THE OCEAN ANNUALLY FROM INFESTED 
WOODLANDS NEAR THE COAST. 
At the rate of 266 first-stage larva? caught on 450 square feet of 
tanglefooted wire at Salisbury Beach in 1913 (being located 1 mile 
from the nearest infested woodland), a basis is given for estimating 
the huge numbers borne into the ocean each year. At the same 
ratio a continuous screen 1 mile long and 6 feet high would have 
caught 18,726 larva?. Judging from the altitude, 300 feet above sea 
level, where quantities were caught at Merrimac. Mass.. it is apparent 
that this number should be fifty times as much, or 936,300 per mile. 
There is now upwards of 450 miles of coast line infested in New 
England (PI. VII), and figming that general spread by wind occurs 
over one-half of this distance, the ocean swallows up annually over 
210,000,000 small larva?. The number is probably much greater 
than is here indicated, as it is not known how many of the small 
larva? passed through the wire meshes of the screen which is used as 
a basis for these figures. 
These calculations, which are partly theoretical, serve to indicate 
what might have been the result with regard to the area infested had 
the moth first been introduced 100 miles farther westward than Med- 
ford, Mass. It also emphasizes the necessity of keeping this moth 
confined to New England territory, if rapid and general spread over 
the United States is to be prevented. 
