492 Illinois State Laboratory of Natural History. 



light and dark browns, yellows, and greens, which, owing to 

 the translucency of the integuments, are seldom sharply 

 defined. They appear to be more definite on preserved 

 specimens, and certain metameric features and resemblances 

 to the plan of coloration of P. parasitica are recognizable. 

 The light marginal spots are present with the same regularity 

 as in that species. The light median stripe may usually be 

 distinguished at the anterior, and less frequently at the 

 posterior, end. It is constricted or quite interrupted by the 

 dark color of the neural annuli, which encroaches on it, 

 while in the intervals between them the light color extends in 

 narrow bands more or less laterad. In the middle region of 

 the body short longitudinal median brown or brownish green 

 lines alternate with light spots. The former correspond to 

 the constrictions, the latter to the expansions, of the median 

 stripe of P. parasitica. Sometimes there is a very distinct 

 continuous narrow median dark brown line. The rest of the 

 dorsal surface is generally variegated browns, with the 

 papillte light yellow or green and the position of the dorso- 

 lateral sensillae indicated by rather large and conspicuous 

 light spots. 



Habits. — A species of sluggish habit; abundant in running 

 waters, where it is found clinging to the under sides of stones. 

 It also attaches itself to the under side of floating wood in 

 ponds and ditches. Particles of mud cling to the mucous 

 secretion on the body and render it inconspicuous, and the 

 leeches frequently bury themselves partially beneath the 

 sediment at the bottom. They seldom swim, but creep along 

 the surface to which they are attached. If thrown into the 

 water they roll up and sink to the bottom. They carry 

 the eggs or young in early spring, a habit which is common 

 to most members of the family. 



