GALLS CAUSED BY FLIES 6i 



I mm. in diameter, on the gills of PlemotMS-astreatus, 

 Tricholoma personatum, T. sordidum, T. nitttm, and CUtocyhe sp. 

 Each tubercle consisted of a fine whitisll pubescence, and con- 

 tained either the egg of a fly, a fragment of earth, or grain 

 of sand, or, very frequently, excreta of a larva. Excepting, 

 perhaps, those arising from the presence of an egg, these 

 productions cannot be looked upon as true galls. 



In 18,99 Vogler alluded to httle isolated or gregarious 

 bodies, 10 to 15 mm high, of variable shape, on the surface 

 of a mushroom. The extremity of each was rounded, 

 provided with a mouth less than 2 mm. in diameter, and 

 contained a cavity 7 to 8 mm. long. The following year 

 Riedel discovered that these tubercles were caused by a 

 Dipteron belonging to the genus Ditomyia, many members 

 of which pass the larval state in woody fungi. 



In 1B99 and 1900 Riibsaamen published an illustrated 

 note on similar tubercles found on the pileus of a Polypoms. 

 Each tubercle was subcylindrical, 5 to 8 mm, high, provided 

 at its apex with a large crateriform opening margined by 

 a deep black zone. The internal cavity was a tube 7 to 10 mm. 

 long, with walls of a firmer consistency than the tissue of 

 the normal fungus. His figure depicts these galls grouped 

 together on the margin of the fungus adjacent to the 

 hymenial surface. 



In 1903 Thorn recorded in the Botanical Gazette, Chicago, 

 that Omphalia campanella Batsch is sometimes deformed by 

 the larva of a fly. Dr. Ross* has recently figured the 

 hymenial surface of Fomes applanatus,, bearing cylindrical 

 tubercles 8 by 4 mm. 



Mr, C. G, Lloyd, the well-known American mycolo- 

 gist, published in his Mycological Notes, April, 1911, the 

 following note : " While collecting at Albany I noted a 

 Myxomycete with curious chimney-like tubes, that on 

 examination proved to be the home of some insect — some 

 sort of ' fly,' I judge. The Myxomycete is Enteridium 



* "Die Pflanzengallen (Cecidien) Mittel und Nordeuropas," 191 1, 

 Taf. iv.. Fig. 75. 



