THE CONTROL OF BLOOD-SUCKING LEECHES, WITH 

 AN ACCOUNT OF THE LEECHES OF PALI- 

 SADES INTERSTATE PARK 



By Dr. J. Percy Moore 

 Professor of Zoology, University of Pennsylvania 



CONTENTS 



1. Introduction. 



2. Description of Carr Pond and the Leech Prolilem. 



3. The Species of Leeches in Carr Pond. 



4. The Natural History of MacrohdcUa decora. 



Description. 



Distribution, Habits and Ecological Relations. 



5. Methods of Control. 



Baiting and Trapping. 



Gathering the Leeches and their Egg-cases. 



Use of Natural Enemies. 



Use of Poisons and Repellents. 



Freezing in Winter Quarters. 



6. References to Literature. 



INTRODUCTION 



In the spring of 1919 Dr. Charles C. Adams, of the New York 

 State Cohege of Forestry, acting on behalf of the Commissioners of 

 Palisades Interstate Park, consulted me concerning the possibility of 

 exterminating or repressing the blood-sucking leeches that infested 

 certain of the lakes and ponds in the Park to the annoyance and 

 alarm of bathers. I was engaged, at that time, under the auspices of 

 the United States Bureau of Fisheries, in continuing a study of the 

 control of mosquitoes by natural biological agencies in the fresh 

 waters of the northern States which had been begun the previous 

 summer as a piece of war work. A cooperative plan was therefore 

 arranged between the Bureau of Fisheries, the College of Forestry 

 and the Park Commissioners, by which work on the two problems 

 could be conducted simultaneously. Accordingly I spent most of 

 July and August of 1919 in field work at the Harriman section of the 

 Palisades Interstate Park. Headquarters in the Park were established 

 at the Guest House on Little Long Pond (Upper Kanahwauke Lake) 

 where excellent living accommodations and field laboratory facilities 

 were provided by the Commissioners. After a preliminary examina- 

 tion in company with Dr. Adams, Carr Pond was selected as the 

 most favorable place for investigation and experiment, although visits 

 were made to many other bodies of water within the Park. The 

 results of the cooperative investigations on the control of mosquitoes 



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