UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 808 



Contribution from tlio Bureau of Entomology 

 L. O. HOWARD. Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



February 24, 1920 



STUDIES ON THE LIFE HISTORY AND HABITS OF THE 

 JOINTWORM FLIES OF THE GENUS HARMOLITA (ISO- 

 SOMA), WITH RECOMMENDATIONS FOR CONTROL.^ 



By W. J. Phillips, 

 Entomological Assistant, Cereal and Forage Insect Investigations. 



CONTENTS. 



Page. 



Introduction 1 



Species infesting tlie grain crops 2 



The wheat jointworm (Harmo- 



lita tritici Fitch) 2 



The wheat straw-worm (H. 



grandis Riley) 5 



The wheat sheath-gall joint- 

 worm (S', vaginicola Doane)_ 8 

 The barley jointworm (H. lior- 



dei Harris) 11 



The rye jointworm (H. secalis 



Fitch) 13 



The rye straw-worm (H. websteri 



Howaxd) 14 



Species infesting the cultivated 



grasses 15 



The timothy straw-worm (H. al- 



lomaculata Ashmead) 15 



The orchard grass straw-worm 

 (H. dactyUcola Phillips & 



Emery) 16 



The blue-grass jointworm (H. 



captiva Howard) 16 



Page. 

 Species infesting the cultivated 

 grasses — Continued. 



The blue-grass straw-worm (H. 



poae Phillips & Emery) 17 



The festuca jointworm (H. fes- 



tucae Phillips & Emery) 18 



Species infesting wild grasses 19 



Harmolita maculata Howard 19 



H. atlantica Phillips & Emery__ 19 

 H. agropyropMla Phillips & 



Emery 20 



H. elymi French 20 



H. ■elymicola Phillips & Emery_ 21 



H. elymivora Phillips & Emery_ 21 



H. ruftpes Phillips & Emery 21 



H. Hesperus Phillips & Emery — 22 

 E. elymophthora Phillips & 



Emery 22 



E. ovata Phillips & Emery 22 



Species whose biology is unknown- 23 



Control measures 23 



Literature cited 26 



INTRODUCTION. 



Owing to the chaotic condition existing until recently in the classi- 

 fication of the genus Harmolita (Isosoma), it has been practically 

 impossible to obtain specific determinations, and this fact has largely 

 prevented economic workers from undertaking detailed life-history 

 studies of the various species. Some members of this genus are of 

 great economic importance, the losses directly traceable to them 



* The writer wishes to acknowledge his indebtedness to various members of the branch 

 of Cereal and Forage Insect Investigations who furnished material from time to time for 

 breeding work, but more particularly to Messrs. W. T. Emery, Philip Luginbill, and 

 T. H. Parks, and to Dr. Henry Fox, who have been associated with him and have ren- 

 dered valuable assistance in breeding, and to Mr. A. B. Gahan for kindly criticisms of 

 the manuscripts. 



132861°— Bull. 808—19 1 



