CONTENTS. 



Department Bulletin No. 326. — Birds of Porto Rico: Page- 

 Introduction 1 



Annotated list of species 17 



Bibliography 130 



Index : . 133 



Department Bulletin No. 327. — The Spruce and Balsam Fir Trees of 

 the Rocky Mountain Region: 



Scope of the bulletin 1 



Generic characteristics of spruces 2 



Generic characteristics of balsam firs 17 



Key to genera 42 



Department Bulletin No. 328. — Milling and Baking Tests op Wheat 

 Containing Admixtures of Rye, Corn, Cockle, Kinghead, and Vetch: 



Introduction 1 



Frequency of occurrence of impurities in wheat 2 



Comparison of the specific gravity of wheat and of its impurities 2 



Methods of preparation and milling 3 



Descriptions of the different impurities 5 



Comparative milling yields of wheat and of its impurities 10 



Milling and baking tests of wheat containing impurities 10 



Tests with flour blends 17 



Tests with wheat containing kinghead seed 18 



Tests with wheat containing wild vetch seed, as grown 19 



Analyses of wheat, of the impurities, and of flour containing admixtures. . 20 



Special cleaning devices ' 22 



Mechanical analyses of corn-cockle screenings 22 



Summary 23 



Department Bulletin No. 329. — Notes on Five North American Buf- 

 falo Gnats of the Genus Simulium: 



Introduction 1 



The adult stage 2 



The egg stage : 11 



The larval stage 12 



The pupal stage 23 



Life cycle and number of generations 26 



Insect enemies and parasites 27 



Simulium as a possible carrier of disease 28 



Bibliography 35 



Department Bulletin No. 330. — The Milling of FacE and its Mechan- 

 ical and Chemical Effect upon the Grain: 



Introduction .* . 1 



Milling methods 4 



Effects of milling on rice 14 



Milled rice and its by-products 22 



Summary 29 



Department Bulletin No. 331. — The Handling and Shipping of Fresh 

 Cherries and Prunes from the Willamette Valley: 



Introduction 1 



Purpose of the investigations 2 



Outline of the experiments 3 



Causes of decay in transit 4 



Cherry investigations 4 



Prune investigations 13 



3 



