1911] 



Muttkowski, Studies iii Tetragoneuria. 



!()•") 



o . — Similar to the male. Middle femora often luteous. Segment 

 10 of abdomen with small lateral spots of yellow. Vulvars divaricate, 

 flattened, the tips subacute. Appendages short, spiculiform, pointed. 



Length abdomen (incl. app.) 27-31 mm., hind wing 27-31 mm. 

 Though exhibiting some variability, the appendages of cynosura are 



Figure 3. — T. cynosura Say. The two bottom figures to the left are 

 from a male (B12) which approximates T. wHliamSOni. 



distinctive from those of the two preceding species and semiquea. 

 Occassionally a specimen, such as B12, approaches Stella, but if the 

 regional difference be taken into account there is little difficulty in 

 separating the forms. 



In width of the abdomen there is much variation. The series 

 from Wisconsin. F10-F30, shows much variability. Thus Fn is 



