GALLS CAUSED BY FLIES 
61 
i mm. in diameter, on the gills of Pleuvotus ostveatus , 
Tricholoma pevsonatum, T. sordidum, T. nudum, and Clitocybe sp. 
Each tubercle consisted of a fine whitish 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 1899 Vogler alluded to little 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 1899 and 1900 Riibsaamen published an illustrated 
note on similar tubercles found on the pileus of a Polypovus. 
Each tubercle w r as 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 Thom 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 Entevidium 
* “Die Pflanzengallen (Cecidien) Mittel und Nordeuropas,” 1911, 
Taf. iv., Fig. 75. 
