394 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 68. 



Genus BRACHYPREMNA Osten Sacken. 



BRACHPYREMNA DISPELLENS Walker. 



On account of its mazy dancing flight, this species is sometimes 

 called the " weaver." The immature stages are spent in decaying 

 wood. The large adults are fairly common in our region, the dates 

 of collection ranging from June 26 to August 11; in copula, 

 July 2. P. I. 



Tribe CTENOPHORINI. 



KEY TO GENERA. 



1. Antennpe of the male with three pectinations on each flagellar segment, a 

 single pectination on the apical half in addition to the usual basal pair; 



ovipositor of the female greatly elongated, saber-like Tanyptera (p. 394). 



AntennjB of the male with two pairs of pectinations on each flagellar seg- 

 ment, one pair being subbasal and the other subapical; ovipositor of the 

 female short and of normal Tipuline structure Ctenophora (p. 394). 



Genus TANYPTERA Latreille. 



KEY TO .SPECIES. 



1. Wings smoky black, body coloration black, the male with the feet and abdo- 



men also black, the female with the feet and base of the abdomen red- 

 dish yellow T. fumipennis (p. 394). 



Wings not black 2. 



2. Wings tinged with topazine yellow, the stigma dark brown; body coloration 



varying from black to yellow, the feet reddish yellow. (Regional) 



T. topazina. 

 vVings hyaline, the stigma brown ; head black, body coloration varying from 



black to yellow T. frontalis (p. 394). 



The immature stages of species of this genus are spent in wood 

 that is relatively sound, the larvae tunneling through the bark and 

 xylem. 



TANYPTERA FRONTALIS Osten Sacken. 



Plummers Island, May 28, 1916, H. L. Viereck. 



TANYPTERA FUMIPENNIS Osten Sacken. 



Great Falls, Virginia, May 24, 1915, C. T. Greene; May 23, 1918, 

 McAtee ; Dead Run, Virginia, May 21, 1916, R. C. Shannon ; May 25, 

 1916, T. A. Keleher; May 27, 1917, F. C. Craighead; Plummers 

 Island, April 12, 1915, bred from maple log, R. C. Shannon; May 

 29, 1902, Geo. P. Engelhardt ; June 7, 1913, H. S. Barber. 



Genus CTENOPHORA Meigen. 



KEY TO SPECIE.S. 



1. Wings with the entire apex beyond the cord tinged with blackish. (Re- 

 gional.) C. apicata Osten Sacken. 



Wings nearly hyaline, with a large brown cloud between the cord and th< 



wing tip but not reaching the apical margin. (Regional.) . 



C. nubecula Osten Sacken. 



These species are locally conmion where found but have not yet 

 been collected in our region. Their immature stages occur in decay- 

 ing wood. 



