12 
IOWA ACADEMY OF SCIENCE Voi.. XXVIII, 1921 
The Tactual Analog of Stroboscopy. L. E. Dodd 113 
The Scattering of X-Rays in Carbon. C. W. Hewlett 
A New Eoud Speaking Telephone Receiver. C. W. Hewlett. .... 
Hall Effect in Thin Silver Films. J. C. Steinberg 115 
The Alpha Eines in the ‘K’ Series Tungsten Spectrum. Charles Cro- 
futt 117 
The Blackening of a Photographic Plate as a Function of Intensity of 
Monochromatic Eight and Time of Exposure. P. S. Helmick 119 
A Note on Nova Cygni, No. 3. D. W. Morehouse 
Review of Solar Observations at Alta, Iowa, During the Past Thirteen 
Years, 1908-1920. David E. Hadden.. 121 
Zoology 
The 1921 Outbreak of the Clover-leaf Weevil in Iowa. H. E. Jacques 127 
A Baltimore Oriole Census. H. E. Jaques and Katherine Gilmore.. 131 
Nactarina in the United States. Frank C. Pellett 
Corn Oil Cake Meal for Growing and Fattening Pigs. John M. Ev- 
vard 135 
Notes on the Mammals Observed in Marshall County, Iowa. Ira N. 
Gabrielson 147 
Bird Banding and Incidental Studies. Dayton Stoner 151 
Burrows and Burrowing Habits of the Common Mole. A. V. Arleton 
Some Observations on Certain Cladocera. Frank A. Stromsten 
Alcohols as Factors Altering Fatigue Processes in Frog Muscle. 
Francis M. Baldwin 161 
Analysis of Certain Smooth Muscle Responses. B. M. Harrison and 
Francis M. Baldwin 179 
Notes on the Differential Viability in Gambusia. S. W. Geiser 197 
The Distribution of the European Elm Scale. Albert Hartzell 201 
Further Studies of the Relative Position of the Maxima Contractions 
of the Amphibian Muscle when Subjected to the Various Ranges in 
Temperature. R. E. Parker 
Cytology of the Earge Nerve Cells of the Crayfish (Cambarus) (Ab- 
stract). E. S. Ross 
The Readjustment of the Peripheral Eung Motor Mechanism after Bi- 
lateral Vagotomy. T. E. Patterson ; 207 
Methods of Teaching Parasitology. Herbert R. Werner 215 
A New Trematode Parasite of the Unionidae. Harry M. Kelly 
Insect Parasitism with Special Reference to Parasitic Diptera. Ivan E. 
Ressler 
Botany 
Notes on the Genus Catharinea in Iowa. 1. Eucy M. Cavanagh 223 
The Use of Common Names for Plants. B. Shimek 225 
The Genus Ceanothus in Iowa. B. Shimek 230 
A Prairie Grove in Eastern Illinois. B. Shimek 
Some Noteworthy Fungi from South Carolina. Guy West Wilson... 
Dr. Rudolph Gmelin and his Collection of Minnesota, Wisconsin and 
Iowa Plants. R. I. Cratty 247 
Two Additions to Our Eist of Cruciferae. R. I. Cratty 256 
