CONTENTS 



Descriptions, Records and Notes on North American Nyssoni- 



dae (Hymenoptera). By J. Chester Bradley 113 



(Issued June 7, 1920.) 



Descriptions of New North American Anthomyiidae (Diptera). 



By J. R. Malloch 133 



(Issued June 12, 1920.) 



Revisionary Studies in the Genus Arenivaga (Orthoptera, 



Blattidae, Polyphaginae). By Morgan Hebard 197 



(Issued June 17, 1920.) 



