CONTENTS. 7 



Department Bulletin No. 245. — Further Experiments in the Destruc- 

 tion op Fly Larvae in Horse Manure — Continued. Page- 

 Effect of hellebore on plants and chickens 19 



Summary - - 20 



Comparative advantages of borax and hellebore 21 



. Literature cited 22 



Department Bulletin No. 246— Vitrified Brick Pavements for Country 

 Roads: 



Introduction 1 



The raw materials 2 



The manufacture 3 



Physical characteristics 5 



Testing the brick 6 



Construction 8 



Cost oi brick pavements 19 



Maintenance of brick pavements 20 



Conclusion 21 



Appendix A 22 



Appendix B - 31 



Department Bulletin No. 247. — A Disease of Pines Caused by Cro- 

 nartium Pyriforme: 



History of the fungus 1 



Morphology of the fungus 2 



Synonymy and description of the fungus 3 



Inoculation experiments with the fungus 5 



Distribution of the fungus 8 



Dissemination of the fungus 12 



Effect of the fungus on its host plants 13 



Eradication and control of the fungus 16 



Literature cited 20 



Department Bulletin No. 248.— ^Pleas: 



Introduction 1 



Hosts of fleas 2 



Biting habits 3 



Life history .• 4 



Length of life of the adult 7 



Breeding places .' 8 



Factors influencing flea abundance 9 



The jumping of fleas and other means of spread 10 



Fleas as carriers of disease 11 



Fleas as parasites of man and animals 16 



Natural control 22 



Artificial control 23 



Remedies for bites 31 



Department Bulletin No. 249. — Portland Cement Concrete Pave- 

 ments for Country Roads: 



Introduction 1 



Materials and construction 3 



Methods, organization, and equipment 19 



Cost of concrete pavements 25 



Maintenance 27 



Conclusion , 29 



Appendix 30 



Department Bulletin No. 250. — Food Plants of the Gipsy Moth in 

 America: 



Scope of the investigations 1 



Equipment of the laboratory 4 



Methods of conducting laboratory experiments 4 



Difficulties in conducting the experiments 5 



Food plants tested 5 



Combination -tray experiments 27 



Classification of food plants 33 



The forest problem 35 



Recommendations for orchard practice 35 



The city problem 36 



Index of food plants used in the experiments 36 



