264 W. S. MARSHALL. 



leader returned again ; 8:42, he starts out again but none follow ; 

 in two minutes he returns to the bunch himself and starts a third 

 time, this time some follow but t soon return to bunch and leader 

 goes off by himself. 



2. Eighteen in line. 8:32, leader removed ; 8:38, bunched ; 

 leader returned and they remained in bunch all morning. 



3. Thirteen in line. Same thing happened as in number two. 

 In one lot, thirty-six in line, the leader had been marked and 



the line allowed to go on. The leader reached the last cater- 

 pillar in the line so that a circle was formed. They all kept 

 moving, the leader finally reaching the place where he was when 

 the circle was first formed ; he then went half way around the 

 circle and started off in another direction the others following. 



From the above, it will be seen that the removal of the leader 

 affects the whole line, but that he is not necessary for the further 

 progression of the caterpillars. I have been unable to find refer- 

 ences to the procession-caterpillar, but notice that the caterpillars 

 of Satnrnia io l march when young the same as the Maia-moth. 



Dubois 2 notes that the procession-caterpillar spins a thread 

 which the others in the line follow ; the young larvae of Hemilcnca 

 do the same, the thread being seen with a hand lens back of the 

 line. In nearly all of the long lines, which the larvae form, there 

 is very apt to be at least one break where there is an inch or 

 more between the nearest caterpillars, or such a break can be 

 made by stopping one of the larvae until the preceding ones 

 have gone ahead for some distance : at such a place the thread 

 also can be seen. When a break occurs, it does not in any way 

 affect the movements of the line, the caterpillars following along 

 the regular path. 



Wishing to see how much the caterpillars depended upon this 

 thread to enable them to follow in the exact path of the leader, I 

 removed the thread a number of times when the distance between 

 two neighboring caterpillars was great enough, and found that 

 the course was not in the least altered. The caterpillars, upon 

 reaching the end of the broken thread, generally kept straight 

 on as if nothing had been done, failing to show a dependence 



1 nickersoii, Mary C., " Moths and Butterflies," 1901. 



2 Dubois, .-/;///. Soc. Linn. Lyon., XLXL, 1900, p. 125. 



