184 Proceedings of the Biological Society of Washington. 



X. FELIX Loew. — Falls Church, Va., June 16, Banks. 



X. FLA viPES Loew. — Occurs everywhere and is fairly numerous; ex- 

 treme dates of collection are: May 3 to October 10. Flies among herbage 

 seldom more than a few feet above the ground. 



Aliograpta Osten Sacken. 



A. OBLiQUA Say. — Very common ; May 3 to October 26. Occurs on 

 Ceanothus and other llowers ; was seen swarming in large numbers in 

 open pine growth at Dead Run, Va., June 29, 1915, Shannon. Larvae 

 feed on aphids, Greene. 



Mesogramma Loew. 



M. GEMiNATA Say. — Omnipresent and very abundant, April 23 to Octo- 

 ber 14. 



M. MARGiNATA Say. — Omnipresent and very abundant; April 4 to No- 

 vember 14. In copula as late as October 25. The species of Mesogramma 

 occur near or on flowers and near aphid-infested plants ; the larvae feed 

 on aphids. 



M. POLiTA Say — Very abundant and widely distributed ; June 22 to 

 October 28. Oviposition seems sometimes to be very carelessly done, 

 specimens observed near Little Falls, D. C, August 22, 1915, were extrud- 

 ing eggs wherever they alighted, on any leaf, and even on the observer's 

 hands and clothing (McAtee). 



Sphaerophoria St. Fargeau and Serville. 



S. CYLiNDRiCA Say. — Omnipresent and very abundant; has been taken 

 from April 6 to October 21. Often about flowers, known to visit those of 

 Salix humilis, Brassica, Ceanothus, Daucus, and Anthemis cotula. In 

 copula May 31. 



S. SCRIPTA Linnaeus. — Great Falls, Va., October 21, Banks; Maryland 

 near Plummers Id., May 28, 1914, Shannon; Cabin John, Md., May, 

 1915, J. C. Crawford; Chevy Chase, Md., May 9 and 13, 1915, G. E. 

 Quinter. 



Pelecocera Meigen. 

 P. PERGANDEi WilHston. — Virginia, November 16, 1879, Theo. Per- 

 gande, the type specimens probably collected at Chain Bridge; Great 

 Falls, Va., October 21, Banks, October 22, 1915, Greene; flying over low 

 plants about 15 inches from the ground ; has also been taken on flowers 

 of wild mustard. 



Sphegina Meigen. 



S. CAMPANULATA Robertsou. — Great Falls, Va. , April 28, 1915; Virginia 

 opposite Plummers Id., May 11, 1916. Greene, flying near base of tulip 

 tree or hovering near low foliage along a stream; Dead Run, Va., May 

 9 and 19, 1916, Shannon. (In my opinion the Sphegina here recorded as 

 campanulala are merely specimens of S. rufiventris that have not attained 

 full color, McAtee. ) 



