MEANS OF SPREAD 41 
in this way that the San José scale was brought to the United States, 
and similar circumstances made possible the introduction of the brown- 
tail moth. 
Various substances used as packing for manufactured products im- 
ported from the far corners of the world may harbor threatening insects. 
Fruits, fruit products, or other edibles imported for consumption 
in the United States may, and often do, introduce injurious species. 
Undoubtedly the majority of the pests thus aecidentally introduced 
fail to become established and never are heard from. But if only an 
oceasional species gains a foothold and multiplies, the results are 
sufficiently disastrous. 
Finally, it happens sometimes that living specimens are imported 
for experiment or study, and through accident are allowed to escape. 
The best-known example of this is found in the gypsy moth, now cost. 
ing New England millions of dollars in attempted suppression or control. 
