THE LEECHES OF MINNESOTA 79 



Habits — Judging- by the material which represents it in this 

 collection this nearly cosmopolitan species must be much less 

 abundant in the lakes of Minnesota than in many other sections 

 of this country and especially the northeastern portion from Illinois to 

 Maine. It is found everywhere but abounds especially in warm 

 shallow waters of streams, pools and ponds and along the shores of 

 lakes and rivers; it is the common pond leech. In all suitable 

 localities it gathers in numbers on the under sides of stones, sticks 

 and fallen leaves or conceals itself between the ensheathing leaf 

 stalks of rushes and other aquatic plants. Less often it attaches 

 itself to the bodies of larger leeches, such as Macrobdella and 

 Haemopis, to fresh water snails, mussels, fishes, turtles and more 

 rarely to frogs. It is perhaps transported on the legs of aquatic 

 birds. Like most of the Glossiphonia it does not swim, but when 

 disturbed creeps with considerable activity to a place of conceal- 

 ment, when, if still further disturbed, it rolls into a ball in the man- 

 ner of a "pill bug" and falls to the bottom, then quickly unrolls and 

 creeps away to a dark shelter. 



Ordinarily its food consists of small annelids, insect larvae, 

 snails, and small bivalves like Pisidium and its allies. Numbers also 

 congregate and feed upon dead bodies of larger animals, such as 

 crustaceans, fishes and frogs ; and when occasion offers blood will be 

 drawn from injured fishes, frogs and other vertebrates, including 

 the feet of wading boys. Vast numbers frequent the fishing stations 

 along the Delaware River, attracted no doubt by the quantities of 

 bloody offal thrown into the water at such places. Under such con- 

 ditions the stomach of every individual will be distended with blood, 

 and, comparing Castle's description of the alimentary canal with my 

 own observations, I am led to suspect that the capacity of the 

 gastric c?eca may be increased in individuals which habitually sub- 

 sist upon such diet. 



On the other hand this little leech is frequently devoured by 

 the large predaceous leeches, sunfish, perch and other small carniv- 

 orous fishes. Along the shores of tidal rivers, like the Delaware, 

 various species of snipe and sandpipers, which feed on the flats ex- 

 posed at low water, pick them from the shingle and gravel. 



Breeding begins in early spring and extends into the early sum- 

 mer. During the latter part of April and early May almost every 

 individual bears its burden of eggs or young. In streams and ponds 

 of cold water ovi-position occurs later than in warmer waters. In 



