H2 THE LEECHES OF MINNESOTA 



short and long limb is about as one to two and one-third. The penis 

 is a slender filiform organ with a slightly bulbous extremity and is 

 frequently extruded to a length of three times the width of the leeches 

 body. The male orifice is on the anterior part of XI b6 or, less fre- 

 quently, between this and the preceeding annulus. 



The paired ovaries are situated in the posterior part of XIV dor- 

 sad of the nerve cord and in contact with the second pair of testes. 

 There is a large albumen gland and a long narrow common oviduct 

 which opens into the narrow anterior end of the pyriform ovisac lying 

 in somite XVI. From the posterior end of the latter a long, slender, 

 much convoluted vagina reaches to the female orifice at XII b6 or XII 

 b$!b6. 



Hcemopis marmoratis includes many color varieties. The ground 

 is usually some shade of green, olive green or greenish brown, some- 

 times nearly plain, sometimes remotely spotted, but usually thickly 

 and confluently blotched with irregular or intermixed spots of lighter 

 grays and darker browns or black. The lighter kinds tend to pre- 

 dominate on the ventral side, from which the darker pigments may be 

 altogether absent. The darker markings are sometimes so close on 

 the dorsal surface as to produce an almost black color. 



Habits — The horse leech, as this species is called, is found in 

 practically all parts of North America, where it has a known wider 

 range than any of its near allies. It is semi-aquatic, living in the 

 mud by the sides of ponds, pools, and lakes rather than actually in 

 the water, although it of course moves freely about in the water and 

 is often found in the mud at the bottom. Along tidal rivers the species 

 is most abundant beneath stones on the flats exposed at low water 

 where it lives with several species of true earthworms. At times it 

 wanders some distance away from the waters edge, burrowing in 

 the soil in search of the earthworms on which it feeds ; but it is not 

 terrestrial in the sense in which H. lateralis is, never leaving, so far 

 as has been observed, the near vicinity of water. Besides earthworms, 

 various kinds of aquatic insects and their larvae, aquatic oligochaetes, 

 gastropods and pelecypods are pursued and eaten and large quantities 

 of mud containing organic matter are swallowed. The species is also, 

 like many other leeches, a scavenger and great numbers will collect 

 on the body of a recently killed animal thrown into their haunts. 

 Blood is also taken when the opportunity is afforded of attaching it- 

 self to drinking cattle or the legs of boys wading in its haunts. It 

 would be interesting to know if it ever enters the pharynx of cattle. 



