47 
effective tenipeniture is .shovv^ri hy a dotted line, many inter(^sting facts 
in regard to the temperature can be observed. It irmst b(; noted, 
however, that the number of larvje caught on any given day is influ- 
enced by the temperature of the preceding da}', as most of the larva? 
enter the bands at night, some time before midnight, and that they 
are usually killed and counted some time the following morning, 
while the observations upon the temperature were taken at a. m. 
Fig. 6. — Weekly summary of Mr. Gibson's band record. 
and 6 p. m. The great rise which occurred on June 2-i was probably 
due in a great measure to the fact that the bands were placed upon 
the trees on the 21st. The fall in the number of larv{i3 on Jime 24, 
the rise on June 27, the fall on June 30, the rise on July 1 and 2, and 
the fall on July 4 can be partially accounted for by the corresponding 
rise and fall of the temj^erature. From about July 5 to August 4 the 
Fig. 7.— Band record made by William A. George, Caldwell, Idaho. In 1901. 
temperatuiH^ was liigh, ])ut there was no corresponding rise m the 
number of larva', as there were no larvje ready to iMiter the bands, the 
majority of the insects being in the moth, egg, and younger larval 
stages. This interval of few larvi^ marks the time between the 
maxima of the generations entering the bands. In the second maxi- 
mum it can be noted that the rise and fall of the number of larva* is 
