A preliminary study of teosinte in its region of origin. Irving E. Melhus and Iris McKy. Chamberlain 139

Apparatus for extraction of microquantities of lipids. John K. Scoggin and Oscar E. Tauber 165

Effect of summer mulches on yields of everbearing strawberries, soil temperature and soil moisture. E.L. Denisen, R.H. Shaw and B.F. Vance 167

Identification and colorimetric determination of the oxidases of corn root tip. Eileen L. Ginter and Frederick G. Smith 177

Some limnological features of Clear Lake, Iowa. William G. Pearcy 189

Three years' study of DDT residues on corn plants treated for European corn borer control. Jack E. Fahey, T.A. Brindley and Harold W. Rusk 209

Studies of temperature and humidity at various levels in crop cover with special reference to plant disease development. J.R. Wallin and R.H. Shaw 261