4 BULLETIN 1093, U. S. DEPARTMENT OF AGRICULTURE. 
OBSERVATIONS ON WIND DISPERSION. 
To determine the number of caterpillars blown upon this bog, 
traps were located at points shown on the map (Fig. 1) and con- 
tinuous observations taken during the period in which the larvae 
PASTURE 
Fig. 1. — Sketch map of Muddy Pond Bog, showing location of traps. 
were carried by the wind. Record was made of temperature, with 
Draper self-recording thermometers, one at the bog level and an- 
other at the top of the observation tower described later; and wind 
