46 



bands. When counted the 

 larvse were killed, which 

 reduced the number of 

 larva3 of the succeeding 

 generation. If the tree 

 from which the record is 

 taken should be covered 

 with rough bark or have a 

 large number of holes and 

 cracks in it, the number of 

 larvffi entering the bands 

 will not be so great as if 

 the band were the only 

 place in which they could 

 hide to spin their cocoons; 

 therefore, filling the holes 

 and scraping away the 

 rough bark would cause a 

 rise in the curve. 



In most cases the con- 

 ditions which would ren- 

 der the records inaccurate 

 were eliminated when it 

 was possible to do so. In 

 order to show the relations 

 between the daily and the 

 weekly band records, a 

 weekly summary (fig. 6) 

 was made of Gilxson's daily 

 band record. By this 

 means it was shown that 

 the weekly records are 

 only approximate, and 

 show the general trend of 

 the insect in the orchard 

 rather than any details. 

 One writer has suggested 

 that the rise and fall of 

 the temperature would 

 cause a corresponding rise 

 and fall in the number of 

 larvse, so as to obscure the 

 true position of the maxi- 

 mum. B}^ a study of the 

 record made by Mr. Gib- 

 son (tig. 5), in which the 



