204 



the Mackinaw bottoms in Woodford county, 111., T have found large 

 numbers late in the fall hibernating in hollow trees about five feet 

 above the ground. A very large colony — perhaps several hundred 

 specimens — was once found some little distance from woods along a 

 moist railway embankment south of Bloomington. 111. Baker ('02, 

 p. 208) states that the eggs, from twenty to eighty, are laid early in 

 June and hatch in about thirty days. 



Pyrarnidiila perspectiva Say. 



The decayed stump in the upland forest (Sta. IV, a) which was 

 overgrown with a layer of fungus (see under P. carolincnsis) con- 

 tained Aug. 17, a very large number of young and adults of this 

 species (No. 71). The shell is distinguished by the large open um- 

 bilicus, which leaves the upper whorls exposed. 



This is the most abundant mollusk in the forest. It was found 

 associated with Circinaria concava, Zonitoides arborea, and Phil- 

 oiJiyciis carolincnsis. In small cavities in the wood encrusted with 

 the fungus, large numbers of P. perspectiva were found crowded to- 

 gether. Apparently this snail fed upon the fungus, the moist surface 

 possibly adding attractiveness. In this stump was a large nest of 

 the ant Aphccnogastcr fidva (No. 79) and one of white ants. Vermes 

 flavipes (No. ^2). P. perspectiva was also taken from a decaying 

 stump on the wooded ravine slope (Sta. IV, h) Aug. 17 (No. 84) in 

 association with Zonitoides arborea, Philomycus carolincnsis, the ant 

 Camponotus hcrcideamis pennsylvanicns, and the beetle Passalus cor- 

 niitus; under decayed logs in the upland oak forest (Sta. IV, a) Aug. 

 17 (No. 88) ; and under a small much-decayed limb on the wooded 

 ravine slope (Sta. IV, b) Aug. 26 (No. 164) in company with Poly- 

 gyra clausa, Vitrea indentata, and Vitrea rhoadsi. 



Shimek ('01, pp. 200, 202) says that this species is common on 

 shaded banks, under decaying logs, and lists it with those which fre- 

 quent "higher, more deeply shaded (often mossy and rocky) banks 

 and slopes, sometimes in deep woods." 



CRUSTACEA 



AsTAcro^ 



Cainbarus diogcnes Girard. Diogenes Crawfish. 



This crawfish was taken Aug. 17, 191 1, in the south ravine (Sta. 

 IV, d), where Mr. Hankinson also took it in 19 10 in the following 

 situations: from a pool in the stream Aug. 17; from burrows, with 

 chimneys, in the bed of the stream, Aug. 20; and from under flat 

 stones in the bed of this stream, three specimens, Aug. 22. 



