| OCR Text |
Show 190 Gills on abdominal segments lobe projecting from dorsal 115); gill lamellae selerotized 2(1) line 2-6 with small margin (Fig. without ventral ••••••••••••••••••••••••••.••••• 2 Body 10-12 mm. in length; posterior margin of head usually straight, occa sionally with shallow median V-shaped notch .•••••••.••••••.•••••.•••••.•.•••.. Body 7-8 R. hageni in length; posterior margin of head modera tely concave .•••••••••..•••..•••.. ___ 3(2) mm. Antero-lateral margin of 3 mesothorax angu larly concave; fibrilliform portion of abdominal gills well developed, almost reaching midline in some specimens (Fig. 115); abdominal sterna usually dark brown •••••••••••..•••••••••••••.••••• lie morrisoni Antero-lateral margin of mesothorax only moderately concave; fibrilliform portion of gills moderately developed; abdominal sterna usually light straight brown or .•••••••.••.••••••••••••••••••••• li. undula ta Rhithrogena futilis McDunnough (Figure 110) Rhithrogena futilis McDunnough, McDunnough (1934) of adults vides collected in description of a presently Taxonomy of described Wyoming. the male this species (1952b) Edmunds imagos; the from a also nymphs series pro- are unknown. and Biology The male those 1934:187. imagos g. hageni of Eaton R. futilis and R. are morrisoni very similar (Banks)f and to can be |
