CONTENTS. 7 



Department Bulletin No. 1117 — Natural Control op the Citrus Mealy- 

 bug IN Florida- — Continued. Page. 



Symptoms of the disease caused by E. fumosa 10 



The fungus in the jji'ove 10 



Relation of fungicides to mealybugs 14 



Department Bulletin No. 1118. — Citrus Scab — Its Cause and Control: 



Economic importance and distribution of citrus scab 1 



Species and varieties attacked 3 



Description of the disease 3 



Review of the literature 5 



The causal organism 8 



Pathological anatomy 12 



Dissemination of the causal fungus 12 



Conditions influencing infection 13 



Growth habits of .grapefruit 20 



Disease as influenced by the stock 21 



Adaptation of the fungus 21 



Inoculation experiments 22 



Spi-aying experiments 27 



Commercial control 30 



Summary 34 



Literature cited 36 



Department Bulletin No. 1119. — Lumber Cut Oi' the LTnited States, 

 1870-1920: 



Introduction 1 



Part I . Signification of declining lumber production 3 



Part II . Statistics of production 24 



Lumber production 24 



Lumber values, by States and species 60 



Lath production, by States 61 



Shingle production, by States 61 



Department Bulletin No. 1120. — Investigations of Heat Canker op 

 Flax: 



Introduction 1 



Anthracnose canker 2 



Heat canker of flax, a nonparasitic type 3 



Cause of heat canker 3 



Similar injury to other plants 14 



Preventive measures 15 



Siunmary 16 



Literature cited 17 



Department Bulletin No. 1121.- — ^The Effects op Inbreeding and Cross- 

 breeding ON Guinea Pigs: III. Crosses Between Highly Inbred 

 Families: 



Introduction 1 



The inbred families 2 



Crossbreeding experiments 2 



Description of tables 3 



Allowance for seasonal fluctuations 5 



Allowance for heredity 10 



Allowance for age of dam 12 



Allowance for sex 12 



Significance of differences 13 



Results 15 



The percentage bom aHve 16 



The percentage raised among the young bom alive 18 



The percentage raised of all young bom 20 



Birth weight 21 



Daily gains 22 



Weight at weaning 23 



Adult weight 24 



Frequency of litters 25 



Age of maturity 27 



Complete sterility 28 



Size of litter 28 



Total fertility • . 30 



