KEY TO AMERICAN INSECT GALLS 



23 



Sorghtim halpense (Johnson grass) 

 Reared from seeds. Dean '10, p. 39 



Itonid. Sorghum midge, Contarinia sorghicola Coq. 



? Digitaria sanguinalis (crab grass) 

 Reduced, swollen head, presumably resembling that of Asteromyia 

 a g r o s t i s, on Muhlenbergia. Coq. '98, p. 71 



Dipt. False spike grass fly, Chlorops graminea Coq. 



Panicum (panic grass) 



Ovipositing in stem. Felt 'o8e, p. 326 



Itonid. Lasioptera panici Felt 



Fig. 18. Black- 

 sheath midge, 

 Lasioptera 



inustorum 

 Felt. Portion of 

 stem showing 



blackened sheath. 

 (Original) 



Fig. 19. 

 Siteroptes 

 c a r n e a Bks. 

 Aborted plant 

 of Aristida 

 purpur ea. 

 (Original) 



Fig. 20. Aster- 

 omyia agros- 

 tis O. S. De- 

 formed head of 

 Muhlenbergia. (Au- 

 thor's illustration) 



Panicum virgatum 

 Blackened leaf sheath infested by orange-colored larvae, length of discolored 

 area 3 cm. Fig. 18. Felt 'i6f, p. 182 



Itonid. Black-sheath midge, Lasioptera inustorum Felt 



Echinochloa crusgalli 

 Occurring in fibrous, somewhat decayed stems of the crown or in the lower por- 

 tions of uninjured stems. Felt 'i6f, p. 181 



Itonid. Grass crown midge, Las'ioptera echinochloa Felt 



Setaria glauca (bristly fox- tail grass) 



Reared from seeds. Dean '10, p. 39 



Itonid. Sorghum midge, Contarinia sorghicola Ccq 



