68 Natural History Bulletin. 



Sub-genus BulimncBa — Hald. 

 L. MEGASOMA. — Say. 



This fine species is not uncommon on floating masses of 

 vegetation in some of the ponds and lakes of the northern part 

 of the state. 



Sub-genus Limnophysa. — Fitz. 

 L. REFLEXA. — Say. 



Very common in the northern and also the eastern part of 

 the state. The longitudinally banded forms known as L. ze- 

 bra are quite common, but it is absurd to consider these as a 

 distinct species. 

 L. palustris. — Muell. 



Locally very common, especially in the northern part of the 

 state. It occurs in swamps on the edges of small lakes. 

 Somewhat variable. 

 L. nuttalliana. — Lea. 



This species which is referred to L. -palustris by Binney is 

 not uncommon in the lakes of the northern part of the state. 

 It certainly is a distinct species. 

 L. DEsiDiosA, — Say. 



Very common on mud-flats at the edges of ponds and slug- 

 gish streams. This is a variable species approaching L. hu- 

 milis in some of its forms and L. pallida in others. The lat- 

 ter may be only a synonym. 



It is also very common in the Loess at Iowa City with L. 

 caper ata and L. hnmilis. Thej'^ occur in a narrow exposure 

 not more than three feet wide in an old railroad cut in the 

 northeastern portion of the city. 

 L. PALLIDA. — Ad. 



A form referable to this species was found by us in several 

 localities. Prof. Witter reports it from Muscatine. 

 L. caperata. — Say. 



Locally very common in ponds in the eastern half of the 



