220 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



parapsides, complete median groove, 15-segmented moniliform an- 

 tennae, and bare wings. Both species have a characteristic "planed- 

 off" appearance of the mesonotum, with the scutellum in the same 

 plane as the mesoscutum. The same is true of the root-gall (or 

 radicicola Dalla Torre) form (agamic generation) of Callirhytis futilis 

 (Osten Sacken). At present Trisolenia has been reduced to synonomy 

 under Andricus (it should have been made a synonym of Callirhytis 

 instead), and if this group of species is ever segregated into a separate 

 genus it would take the name of Trisoleniella Rohwer and Fagan 

 1917 {Trisolenia having been preoccupied by Ehrenberg in Protozoa 

 in 1861). 



Type.— Cat. No. 22573, U.S.N.M. Type and 42 paratype flies. 



Host. — Quercus rubra Linnaeus, Quercus catesbaei Michaux, Quercus 

 myrtifolia Willdenow, Quercus texana Buckley. 



Gall. — In clusters of as many as 150 at the base of young sprouts 

 4-10 cm. underground. Clusters are roughly spherical and may 

 measure 2.5 cm. in diameter. The appearance of the fresh galls is 

 unknown. The type flies are from a disintegrated cluster, and a 

 fleshy layer had evidently rotted away, leaving a hard and brittle 

 shell 4 by 6 mm., longitudinally ridged, with a wall about one-half 

 a millimeter thick. (Plate 33, fig. 20.) The fleshy layer is evidently 

 thin, for in the sandy soils of Florida it seems to dry down on the 

 inner shell instead of decaying as in the more humid northern soils, 

 and the ridges show through. The species was known to the writer 

 years before an intact cluster was found, and it was not until flies 

 were reared from these Florida galls, in 1919, agreeing with the types 

 that the character and appearance of the cluster was known. The 

 galls figured are from Q. catesbaei. (Plate 33, fig. 19.) 



Habitat. — The type flies are from Winnetka, Illinois, where a dis- 

 integrated cluster containing adults was found October 22, 1914, at 

 the base of a young sapling of Q. rubra. Empty galls of this species 

 were also seen at Ravinia and Highland Park, Illinois. Intact clusters 

 of galls were collected at Madison, Florida, October 21, 1919, on 

 Q. catesbaei. They then contained pupae, and adults were cut out De- 

 cember 4, agreeing with the Winnetka specimens. Others were seen 

 at Gainesville, Ocala, Marianna, and Jacksonville. The same species 

 was found on Q. myrtifolia at Carrabelle, Florida, October 19, and at 

 Daytona November 20, and both pupae and adults were found when 

 cut open on December 3. Empty galls were seen on Quercus texana at 

 Boerne, Texas. The United States National Museum has a single 

 similar fly from Jacksonville and a gall cluster from Georgiana, 

 Florida, both without date or host records; also an empty gall cluster 

 from Ocean Springs, Louisiana, collected February 3, 1898, on "Q. 

 'phellos ?." 



