48 Roosevelt Wild Life Bulletin 



The first four camps listed are situated on the old part of the lake, 

 the next three are just within the extension and the remaining four 

 are well wnthin the latter. The table includes only those camps con- 

 cerning which tmequivocal data covering both years are available 

 and upon which the information furnished to Mr. Brown and myself 

 agreed. The data from other camps is confirmator}', so far as they 

 go. Mr. Herbert expressed the opinion that there were fewer leeches 

 in 1920 than in 1919, and in 1919 than in 1918. In reph" to an inquiry- 

 Mr. ^^'elch wrote on November 30 : " From all appearances tliere 

 were as many leeches in Carr Pond during the summer of 1920 as 

 there were during the summer of 1919," and on December eleventh : 

 "All of the information which I have been able to gather seems to 

 show that last 3^ear tlie leeches had certain!}? moved from their former 

 locations and were more prevalent in new sections of the lake and it 

 had occurred to me that this might be due to the fact that when we 

 drew down the waters of this lake the new emptied verv- much more 

 rapidly than the old and the leeches left in the mud in this section 

 were able to get out and down to the water before the final freeze up." 



Second: a personal examination similar to that conducted last 

 summer to determine the abundance and distribution of the leeches 

 was made. While this, of course, does not furnish an accurate census 

 it does give a basis for rough quantitative comparison. In 19 19, 

 twelve stations, representing a variets- of conditions and different 

 parts of the lake shore, were selected for careful examination. So 

 far as practicable these were of approximateh* equal size, that is, 

 each was a section of the shore about fifteen feet long and three feet 

 wide, one foot of the width being landward and tvco feet in the water. 

 The several areas were not accurately measured but only paced off. 

 The general physical and biological conditions were noted. All pieces 

 of timber, sticks, stones or other objects affording places of conceal- 

 ment were lifted and scrutinized and the mud and turf more or less 

 probed and superficially examined. 



All leeches taken within the marked areas were counted, but the 

 figures for Macrobdella only are given in the table. The attempt 

 was not to make the determination quite exhaustive of all the leeches 

 present in each area as this would have involved washing and screen- 

 ing the soil to a depth of three or four inches, but nearh? all were 

 secured by the method adopted. In 1919 each station was examined 

 several times during the stunmer and the figures given show that 

 later examinations invariably yielded a much smaller number of the 

 larger leeches. In 1920 the time was sufficient to examine only six 

 of these stations vrith the same thoroughness as in 1919. The others 

 were examined much more hastily but so far as they go the figures 

 are confirmatorv. 



