INVESTIGATION OF LIFE HISTORY. 



31 



of the paper connected with the reels, and the edges were bent upward 

 in such a manner as to prevent the escape of the larva from the sides 

 of the table. The paper on the reels consisted of ordinary wrapping 

 paper 18 inches in width. The larva was placed in the center of the 

 table and the record of its travels was made with a lead pencil. The 

 experiment was begun at 8.30 a. m., June 18,* 1910, and was conducted 

 by Mr. C. W. Collins, with the assistance from time to time of various 



,-■■ ' ■ '! H, „, 



iP "Til 



Fig. 14.— Method of securing data on the distance traveled by larvse of Calosoma sycophanta. ( Original. ) 



members of the laboratory force. It was necessary to carry on this 

 experiment continuously until the larva died, and as it remained 

 active for 72 hours shifts of men were used so that there was no break 

 in the record. The larva traveled far more rapidly than was expected 

 and it became necessary from time to time to substitute a fresh roll of 

 paper in place of the one containing the record. In all 1 1 rolls were 

 used and careful measurements indicate that during its life the larva 



