MOV 18 1890 



ARTICLE VIII.— ^n American Terrestrial Leech. By S. A. 



FOKBES. 



Our common land leech was first obtained by me in April, 

 1876, at Normal, McLean County, Illinois, where it was dug up 

 in a house garden, about a dozen rods from the nearest rivulet. 

 An example sent the following year to Prof. A. E. Verrill, with 

 some remarks on its superficial characters, was by him iden- 

 tified provisionally and with some hesitation as his Semiscolex 

 grandis, originally described* from three aquatic individuals 

 obtained from Lake Huron, Lake Superior, and West River, 

 Connecticut. I have now, however, fifty-six specimens of this 

 leech, all from the earth in Central Illinois, some of them half 

 a mile or more from water, and representing collections made 

 at different times from April, 1876, to June, 1890 ; while, on 

 the other hand, it has not once occurred in the course of a 

 large amount of aquatic work done in the same regions during 

 these fifteen years. It has, moreover, constant characters 

 which clearly distinguish it from Semiscolex grandis, as far as 

 one may judge by a comparison with Yerrill's description, and 

 I do not doubt that it is distinct. 



Its only known food is earthworms of various genera, and 

 these it swallows entire, as I have repeatedly found by dissec- 

 tion, and demonstrated likewise by feeding experiments on 

 leeches in captivity. 



From the fact that all my specimens were obtained during 

 the early months of the year, — from March to June, — it is 

 probable that this leech, like the earthworm, penetrates to 

 considerable depths during the midsummer drouths. 



DIAGNOSIS. 



Semiscolex terrestris, Forbes. f This is one of the largest 

 of our leeches, my contracted alcoholic specimens reaching a 



* Synopsis of the North American Fresh Water Leeches. By A. 

 E. Verrill. U. S. Commission of Fish and Fisheries. Part II. Report 

 of the Commissioner for 1872 and 1873, p. 672. 



t American Naturalist, vol. xxiv., 1890. 



