'24 SUCCINEIDAE 



SUCCINEA AVARA Say 



Two varieties of Succinea avara are found in Illinois: the 

 typical avara and the smaller form called avara wardiana. 

 This species, containing the smallest of our Succinea snails, 

 is distributed throughout Illinois 

 wherever suitable localities are 

 found. Varied habitats of these 

 snails include oak, elm, walnut 

 and ironwood in hillside regions; 

 oak, elm, birch, beech and maple 

 in floodplain localities; grass, 

 weeds and low bushes on railroad 

 embankments. 



Succinea avara avara Say. Fig. 

 A. The shell of Succinea avara 

 avara sometimes approaches one-half inch (9-12 mm.) in height. 

 Usually thin, it is yellow or somewhat greenish in color. It 

 has 3 convex whorls separated by deep sutures. The body whorl 

 is large, but not greatly expanded, and is ovoid in shape, broadly 

 rounded below and somewhat acutely rounded above. The ap- 

 erture is ovate. The spire and aperture are about equal in length. 

 The young shell is usually covered with dirt that adheres to the 

 rough surface. The vertical line represents actual size of the 

 typical shell. The other shell is proportionally smaller. 



Succinea vermeta of Thomas Say is considered an absolute 

 synonym of avara avara. Say's description of vermeta was 

 based apparently on an immature shell. In the type locality at 

 New Harmony, Indiana, many variations may be found from 

 one with an almost scalariform spire to one in which the whorls 

 are flatly rounded. 



In A Catalogue of the Mollusca of Illinois (page 114), 

 Succinea grosvenorii Lea is listed from Canton, Fulton County, 

 on the authority of Nason and Wolf, two Illinois collectors of 

 mollusks. The shells responsible for this listing were incorrectly 

 identified; they are in reality large specimens of Succinea avara. 

 Succinea avara wardiana Lea. Fig. B. This variety is 

 smaller than the typical avara. The shell, not exceeding a 

 quarter inch (6-7 mm.) in length, is narrower than that of avara 

 avara, and the aperture is more nearly round than that of the 

 typical form. It is found in the habitats indicated for the species. 



