428 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.58. 



LIMNOPHILA TENUICORNIS Osten Sacken. 



Great Falls, Virginia, May 2, 1917, McAtee. 



LIMNOPHILA TENUIPES Say. 



Common ; has been collected from May 20 to October 6 ; comes to 

 light. P. I. 



• LIMNOPHILA TEREBRANS Alexander. 



Cabin John, Maryland, May 5, 1899. 



LIMNOPHILA TOXONEURA Osten Sacken. 



Plummers Island, June 8, 1913, June 2, 1916, McAtee. 



» LIMNOPHILA ULTIMA Osten Sacken. 



Frequent in fall, September 23 to October 23; comes to liglit. 

 V. P. I. 



Tribe HEXATOMINL 



KEY TO GENERA. 



1. Cell /?rsf J/2 open ; ouly one free branch of the media reaching the wing 



margin Hexatoma (p. 428). 



Cell first Ah closed ; two or three free branches of the media reaching the 

 wing margin 2. 



2. Tarsi (in the local species) pure white; stigma small; cell Mi present 



Penthoptera (p. 428). 



Tarsi not white, coneolorous or darker than the rest of the legs; cell Mi 



lacking in the local species Eriocera (p. 429). 



Genus HEXATOMA Latreille. 



* HEXATOMA MEGACERA Osten Sacken. 



Glencarlyn, Virginia, May 1, 1910, F. Knab ; Cabin John Bridge, 

 Maryland, April 28, 1912, J. K. Malloch. There is but a single 

 described American species. The larvae are aquatic, but before 

 pupation they come to earth for a short period. 



Genus PENTHOPTERA Schiner. 



PENTHOPTERA ALBITARSIS Osten Sacken, 



Pimmit Run, Virginia, September 6, 1908, F. Knab ; Difficult Run, 

 Virginia, July 25, 1915, Alexander and McAtee; Dyke, Virginia, 

 July 16, 1916, Mount Vernon, Virginia, June 19, 1918, Beltsville, 

 Maryland, July 30, 1916, McAtee. P. albitarsis is the only known 

 Nearctic species. The immature stages are spent in organic earth 

 in woods, usual W underneath a layer of leaf mold. 



