CONTENTS OF VOLUME XI 

 PLATES 1-41 



Title-page i 



Contents iii 



Notes on a Fauna of the Vigo Group and its bearing on the evo- 

 lution of Marine Molluscan Faunas, by Roy E. Dickerson, 

 published July 6, 1021 1 



A list of the Amphibians and Reptiles of Nevada, with notes on 

 the Species in the Collection of the Academy, by John Van 

 Denburgh and Joseph R. Slevin, published July 8, 1921 27 



A list of the Amphibians and Reptiles of Idaho, with notes on the 

 Species in the Collection of the Academy, by John Van Den- 

 burgh and Joseph R. Slevin, published July 8, 1921 39 



A list of the Amphibians and Reptiles of the Peninsula of Lower 

 California, with notes on the Species in the Collection of the 

 Academy, by John Van Denburgh and Joseph R. Slevin, pub- 

 lished July 8, 1921 49 



Notes on the Birds and Mammals of Siskiyou County, California, 



by Joseph Mailliard, published July 11, 1921 73 



Preliminary diagnoses of new Species of Reptiles from Islands in 

 the Gulf of California, Mexico, by John Van Denburgh and 

 Joseph R. Slevin, published July 30, 1921 96 



New California Spiders, by Nathan Banks, published September 



29, 1921 99 



Undescribed Tipulidae (Diptera) from Western North America, 

 Part II, by Charles P. Alexander, published September 29, 

 1921 103 



Description of a new Species of Pero from California, by W. S. 



Wright, published September 29, 1921 109 



Characters of some new Species of North American Hemipterous 

 Insects, with one new genus, by Edward P. Van Duzee, pub- 

 lished October 15, 1921 Ill 



Our North American Species of Strongylocoris (Hemiptera), by 



Edward P. Van Duzee, published October 15, 1921 135 



Characters of eight new Species of North American Anthocoridae 

 or Flower Bugs, by Edward P. Van Duzee, published October 

 15, 1921 137 



A Study of North American Grass-bugs of the genus Irbisia, by 



Edward P. Van Duzee, published October 15, 1921 145 



Insects of the Pribilof Islands, Alaska, by G. Dallas Hanna, pub- 

 lished November 2, 1921 153 



