The associations of the sand prairie 67 



Method of analysis of tlie animal assemblages 67 



The prairie formation 68 



The bunch-grass association 68 



Phytophagous animals of the bunch-grass 69 



Predaceous animals of the bunch-grass TZ 



Parasitic animals of the bunch-grass 76 



Scavengers of the bunch-grass ^^ 



Invaders from other associations 78 



The Panicum pscudopubcscens association 79 



The black-soil transition association 80 



The blowout formation 82 



The basin association 84 



The windward slope association 84 



The blowsand association 85 



Phytophagous animals of the blowsand '. . 86 



Predaceous animals of the blowsand 87 



Parasitic animals of the lilowsand 87 



Scavengers of the blowsand 87 



The blowsand complex 88 



The fleposit association 90 



Succcssional relationships in the sand i)rairit' 90 



Bil)liography 93 



Explanation of plates 95 



ARTICLE II. THE CYRUS THOMAS COLLECTION OF APHIDI- 

 D^, AND A TABULATION OF SPECIES MENTIONED AND 

 DESCRIBED IN HIS PUBLICATIONS. BY JOHN J. DAVIS, B.S. 



(2 Platf.s) September, 1913 97-121 



ARTICLE HI. STUDIES ON THE ENCHYTR^ID^ OF NORTH 

 AMERICA. BY PAUL S. WELCH, PH.D. (5 Pl.\tes, i Text Fig- 

 ure) March, 1914 123-212 



Introduction 123 



Key to the genera of North American Enchytr?eid?e 125 



Henlea Michaelsen 126 



Key to the species of llciiica known to occur in North America 127 



Henlea moderata, n. sp 128 



External characters 129 



Internal characters 130 



Henlea urbanensis, n. sp 134 



External characters 135 



Internal characters 135 



Lumbricillus Oersted 141 



Key to the species of Lumbricillus known to occur in North America. . 142 



Lumbricillus rutilus, n. sp 143 



