CONTENTS. 7 



Page. 

 Department Bulletin No. 644. — -Lint Percentages and Lint Index or 

 Cotton and Methods of Determination — Continued. 



Increasing the lint percentage does not alter the cost of production if the lint 



index remains constant 8 



Improved methods for obtaining lint percentages 8 



Advantages of using samples of standard weight ] 



Methods of calculating lint indexes and seed weights 10 



Number of seeds in a standard sample an indication of their size 10 



Planters can estimate the lint index 11 



Summary 11 



Department Bulletin No. 645. — Some Reasons for Spraying to Control 

 Insect and Mite Enemies of Citrus Trees in Florida: 



Gradual adoption of spraying 1 



Pests of importance 2 



Injury to trees and fruit 2 



The grading of fruit 3 



Reduction in size caused by insects 8 



Better grades of fruit bring better prices 13 



Spraying scheme for controlling citrus pests 15 



Cost of spraying 16 



Profits and benefits 17 



Conclusion 18 



Department Bulletin No. 646. — Lessons on Pork Production for Ele- 

 mentary Rural Schools: 



Introduction 1 



Lesson I. Types and breeds 2 



Lesson II. Houses 6 



Lesson III. Swine judging 9 



Lesson IV. Fattening meat hogs 12 



Lesson V. Selecting breeding stock 13 



Lesson VI . Dressing and curing meat 15 



Lesson VII. Sow and pig management 17 



Lesson VIII. Forage crops 18 



Lesson IX. Sanitation and diseases 21 



Pig-club work 25 



Department Bulletin No. 647. — The Argentine Ant in Relation to 

 Citrus Groves: 



Introduction 1 



General belief as to damage to orange trees 2 



General account of orange culture in Louisiana 4 



Distribution of the ant in the orange groves of the United States 7 



Feeding habits of the ant 8 



Relations with insects injurious to citrus trees 15 



Relations with insect enemies of scales and aphids 48 



Nests and protective structures of the ant 52 



Cultural conditions in ant-invaded v. ant-free orange groves in Louisiana.. 56 



Demonstration in improvement of ant-invaded groves in Louisiana 57 



Experiments in controlling the Argentine ant 60 



Summary and conclusions 71 



Department Bulletin No. 648. — A Farm-Management Survey in Brooks 

 County, Ga: 



Description of area surveyed 1 



Method and scope of investigation 5 



Type of farming 7 



Tenure and landlord 's profits 13 



Labor systems 14 



Size of business 18 



Quality of farm business 20 



Organization 30 



Cost of production 41 



