20 



BULLETIN 351; U. S. DEPARTMEXT OF AGEICXJLTUEE. 



the larvse by the fine soot deposit upon the smoked paper. The dis- 

 tance traveled varied from 97.7 cm. to 175.8 cm. Figure 6 shows a 

 tracmg made by fom- of the above-mentioned larvae. 



Table XIII. — Record of travel of five first-instar terrapin-scale larvx on smoked paper, 

 Oct. 9. 1912. Mont Alto. Pa. 



No 



1 Start. 



End. 



Time. 



Distance. 



Rate per 

 hour. 



Average 

 temper- 

 ature. 



1 



2 



3 



4 



5 



■ 9.26 a. m . . 



9.26a. m.. 



11.20 a.m. 



10.08 a. m. 



9.26 a. m.. 



2p. m 



3.15 p. m.. 

 2p. m 



2p. m 



2..50p. m.. 



Hrs. Mn. 



4 34 



5 49 



2 40 



3 52 

 5 24 



Cm. 

 113.7 



175. S 

 97.7 

 99.6 



161.7 



Cm. 



26.54 



26. 596 



36.64 



25.76 



29.94 



" F. 

 87 

 S6 

 89 

 87 

 86.7 





\ 



29.095 



s^7 





I 





The larvae are so small that they leave no trace when moving over 

 the finest soot deposit. The deposit, moreover, retards them. In 

 movmg they are constantly exploring the surface -^Adth their antennae, 

 and these soon become coated with soot particles. When this hap- 

 pens the insect halts luitil the antennae are cleaned. (For compari- 

 son with the rate of progress upon smooth, mismoked paper, see 

 Table XIV.) 



A single larva that emerged at 12.10 p. m traveled, when placed 

 upon plam v^Tapping paper, 826 cm. dm'ing the 3 horn's and 20 min- 

 utes m which it was under observation. This larva traveled con- 

 stantly after the first interval, and its speed was about eight times 

 that of larvae on sooted paper. Figure 7 shows a tracing made of 

 this larva. 



Table XIV. — Record of the travel of a newly emerged larva of the terrapin scale on plain 

 iirapping paper, July 10, 1912, Mont Alto, Pa. 



Time of observa- 

 tion. 



Tempera- 

 ture. 



Total dis- 

 tance. 



Interv-al 

 distance. 



Rate per 

 hour. 



Average 

 tempera- 

 ture. 



12.10 p. m 



12.25 p. m 



1 p. m 



° F. 



86 



86 

 .86 



86 



86 



87.5 



87.5 



88 



Cm. 



Cm. 



Cm. 



° F. 



35.3 

 184.4 

 239.3 

 298.3 

 473.4 

 557.2 



35.3 

 149.1 



44.9 



59 

 175.1 



83.8 

 188 



141.2 



255.6 



179.6 



236 



262.65 



251.4 



282 



86 



86 



86 



86 



86.75 



87.75 



88 



1.15 p. m 



1.30 p. m 



2.10p. m 



2.30 p. m 



3.30 p. m 



Average.. 









231.356 



86.9 





i 1 



In 1912 tkree experiments were performed to determine the longev- 

 ity of the leafward migrants when the}^ were unable to reach the 

 leaves. The data from these experiments are recorded in Table 

 XV, and summarized in Tables X^T and XVII. They show that 



