Banks, Greene, McAtee, and Shannon — Dist. of Col. Diptera. 187 



Meromacrus Rondani. 



M. CRCCiGER Wiedemann. — Dead Run, Va., July 15, 1915, Shannon; 

 probably a stray specimen as this species has a more southern range. 



Tropidia Meigen. 



T. ALBisTYLUM Macquart. — Washington, D. C, May 16, 1916, McAtee; 

 June 19, 1915; Marlboro, Md., June 19, 1915, Shannon; Falls Church, 

 Va., June 19, 1914; June 26 and 29, 1912; August 3, 1914, Greene; May 

 5 and 24, July 10, October 21, Banks. Not on flowers but resting on 

 leaves or hovering a foot or more from ground in sunny places. 



T. QUADRATA Say. — Washington, D. C, August 19, 1911, F. Knab. 



Helophilus Meigen. 



H. cHRYsosTOMus Wiedemann. — Common in its chosen habitat along 

 streams and in marshes; May 3 to August 3. 



H. DiSTiNCTUs Williston. — Common in same situations as last species; 

 tlie two often taken at same time ; May 21 to August 3. 



H. Divisus Loew. — Originally described from the District of Columbia 

 (Centuria quarta, p. 78). It seems by no means certain that this species 

 and H. laetus, recorded below, are really distinct. The latter name has 

 page priority. 



H. LAETUS Loew. — Plummers Id., Md., on flowers of Cornus stricta, 

 June 11, 1916, H. L. Viereck. 



H. LUNULATUS Meigen? — ^Maryland near Plummers Id., April 23, 1914, 

 Shannon. 



H. siMiLis Macquart. — Common; season April 12 to October 30; usually 

 near water where it basks in sunshine ; has also been taken at flowers of 

 Salix and Potentilla monspeliensis. 



Mallota Meigen. 



M. ciMBiciFORMis Fallen. — Piney Branch, D. C, no date, D. H. 

 demons; Washington, D. C, May 10, 1911, McAtee; May 17, C. L. 

 Marlatt; June 18, 1908, F. H. Chittenden, July 8, 1913, J. D. Hood; 

 Arlington, Va. , July 10, Wm. Palmer; Falls Church, Va., May 7, Banks; 

 July 23, 1913, Greene; Maryland near Plummers Id., June 26, 1902, 

 H. S. Barber; Plummers Id., Md., May 18, 1912, A. K. Fisher. Larvae 

 have been found in pocket in tulip tree, Greene. 



M. POSTicATA Fabricius. — Bladensburg, Md., June 7, 1916, L. O. Jack- 

 son; Plummers Id., Md., June 14, 1908, McAtee; Maryland near Plum- 

 mers Id., May 21, 1916, J. C. Crawford; May 28, 1916, L. 0. Jackson, 

 H. L. Viereck; Virginia near Plummers Id., May 21 and 28, 1916, H. L. 

 Viereck; June 2, 1916, June 19, 1909, McAtee; Dead Run, Va., May 23 

 and 25, 1915, May 24, 1916, Shannon; Rosslyn, Va., July 7, F. Knab; 



