502 



short distance (Figs. 63, 67, 68), and frequently with one or more 

 light cross-bands and coarsely spotted with dark pigment. 



b. Gills broadest beyond the middle, decidedly ovate (Fig. 63) and 

 frequently with a V-shaped cross-band near the apex ; median lobe 

 projecting between and distad of the articulations of the labial 

 palpi much less than one-third the length of the proximal segment 

 of the palpi (Fig. 11) violacea. 



bb. Gills broadest at middle, elliptical (Figs. 67, 68) and never with 

 a V-shaped mark near the apices ; median lobe of the labium pro- 

 jecting between and distad of the articulations of the labial palpi 



one-third or more of the length of the latter f apicalis. 



1 tibialis. 



ADULTS 



Females 



a. Wings smoky fumipennis. 



aa. Wings not smoky. 



b. Stigma surmounting more than one cell in the hind wing; mes- 

 epimera without a broad dark stripe on each, ventrad of the mes- 

 opleural suture; mesostigmal plates (Fig. 154) with a sharp median 



projection on the caudal margin moesta putrida. 



bb. Stigma surmounting a single cell or less in the hind wing ; mes- 

 epimera with or without (apicalis) a broad dark stripe on each, 

 ventrad of the mesopleural suture; mesostigmal plates without a 

 sharp median projection on the caudal margins. 



c. Front, vertex, and occiput wholly brown ; caudal margins of the 

 mesostigmal plates forming a thin blade which projects dorsad. . . 

 sedula. 



cc. Front, vertex, and occiput with more or less black pigment ; 

 caudal margins of the mesostigmal plates not forming a thin 

 blade which projects dorsad. 



d. Black stripe of the mesopleural suture extending more than 

 half-way to the wing bases from the infraepisternum. 



e. Caudal margins of the mesostigmal plates (Fig. 140) not pro- 

 jecting caudad at the caudo-mesal angles; terga 1-5 of the 

 abdomen with the mesal pale line narrower than the black 

 lines on either side tibialis. 



ee. Caudal margins of the mesostigmal plates projecting caudad 

 at the caudo-mesal angles and forming a rounded lobe (Fig. 

 142) ; terga 1-5 with the pale mesal stripe much broader 

 than the black stripe on either side violacea. 



dd. Black stripe of the mesopleural suture extending less than half- 

 way to the wing bases from the infraepisternum apicalis. 



