CONTENTS 



Page 



Department Bulletin No. 1222. — Geowth and Feeding of Honey- 

 bee Larvae: 



Introduction 1 



Methods, lots 1 to 7 2 



Observations, lots 1 to 7 2 



Weight of eggs 2 



Rate of growth of larvae 3 



Variations in rate of growth 6 



Length of the larval period 6 



Effects of underfeeding 7 



Methods, lot 8 8 



Observations, lot 8 9 



Effect of no honey flow 9 



Effect of stimulation 9 



Nature and composition of brood food 11 



Time of change in composition of brood food 12 



Rate of growth 13 



Correlation of food with the rate of growth 14 



Correlation with time spent in nursing 16 



General appearance of larvae of different ages 16 



Summary and conclusions 18 



Tables 1 to 4 20 



Literature cited 24 



Department Bulletin No. 1223.- — The European Elm Scale in the 

 West: 



Introduction 1 



Importance 1 



History 2 



Synonymy 2 



Distribution and spread 3 



Injury 5 



Food plants _ ^ 6 



Descriptions 6 



Life history and habits 9 



Seasonal history 11 



Natural enemies 12 



Control experiments 13 



Recommendations for control 15 



Summary 17 



Literature cited 18 



Department Bulletin No. 1224. — Relation op Land Income to Land 

 Value : 



Statement of problem 1 



Sources of data and selection of area 3 



Relation of land income to land value in 1920 6 



Accuracy and representative character of the data 10 



Net cash rents and their relation to land value 26 



Factors determining relationship of land income to land value at a 



given time 28 



Long-time tendency in the ratio of land income to value 37 



Anticipated rate of return on investments in farm lands 40 



Actual rate of return on investments in farm lands 46 



Analysis of cash rent as a measure of land income 47 



Bearing of this study on other problems 64 



Appendix 70 



