CONTENTS, 5 



Department Bulletin 185. — Bird Migration — Continued. Page. 



Slow and rapid migration 25 



How birds find their way 27 



^Migration and molting 31 



Casualities during migration 31 



Are birds exhausted by long flight? 83 



Evolution of migration routes 35 



Normal and abnormal migration 37 



Relative position during migration 40 



Relation between migration and temperature 41 



Variations in speed of migration 43 



The unknown 47 



Department Bulletin 186. — ^A Method op Fumigating Seed: 



Inti-oduction 1 



Fumigation chamber 2 



Experiments 4 



Summary 6 



Department Bulletin 187. — Preliminary Census of Birds op the 

 United States: 



Introduction 1 



Previous bird censuses 2 



Plans for the 1914 census 2 



Results in the northeastern States 4 



Deductions from the census ^■.... 7 



Relative abundance of bii'ds 9 



Summary 10 



Department Bulletin 188. — The Importance of Thick Seeding in the 

 Production of Milo in the San Antonio Region: 



Introduction 1 



Causes of unsatisfactory yields : 2 



Extent of sorghum-midge damage during 1913 and 1914 3 



Results of the experiments 3 



Summary 20 



Department Bulletin 189.^ — Studies of the Codling Moth in the 

 Central Appalachian Region: 



Introduction 1 



Localities in which investigations were made 2 



Nature and extent of the investigations 2 



Explanation of the use of terms 3 



Investigations at Charlotte\dlle, Va 4 



Investigations at Greenwood, Va 11 



Investigations at Hagerstown, Md 13 



Investigations at Winchester, Va 21 



Investigations at Fishersville, Va 28 



Investigation.s at French Creek, W. Va 32 



Investigations at Pickens, W. Va 37 



R^'sume of rearing experiments in Maryland, Virginia, and West Virginia. 40 



Number of firHt-h»rood larvse transforming first season 42 



Effect of differences in altitude and latitude upon the development of the 



codling moth 42 



Relati ve numbers of larvse ascending and descending the trees 44 



Seasonal effect of weather conditions on the different stages of the codling 



moth 45 



Cannibalism among codling-moth larvse 45 



Natural enemies 46 



Summary 48 



Dki'aktmk.st Bulletin 190. — The Drainage of Irrigated Land: 



Introduction 1 



ManiffHfalion.s of prior drainage conditions 2 



Spofifif objertH ol draining 2 



Preliminary investigationH 2 



Open 'anai.H 4 



Covered drairif* 5 



('hoiff of \\])C of drain 8 



LfKation of opuu cauaJH 10 



I'e|»th an<l IfK-ation of covered drainu 10 



