| OCR Text |
Show 82 on 7 (Figs. 77-80); front of head entire feebly emarginate, not as above; maxillary palpi normally not visible or from dorsal view 21(20) ••••••••••••••••••••••••••••• 21 Gill lamellae on abdominal segment 1 decidedly smaller than those on segment (Fig. 77); fibrilliform portion of gill 1 longer than lamella (Fig. 77); labrum narrow, extending not more than one-fourth distance along anterior margin of head Cinygma, 2 •••••••••••••••••• Gill abdominal segment 1 only slightly shorter than those on segment 2 (Fig. 78); fibrilliform portion of gill 1 usually subequal to or shorter than lamellae (Fig. 78); labrum broad, extending two-thirds to three-fourths distance along anterior margin of head Heptagenia, lamellae ••••••••••••••• 22(11,13) p. 147 p. 177 on Gills on abdominal segment 1 differ structure from those on succeeding in segments (Figs. 123-126); gills on segments 2-7 bilamellate, terminating in filaments or points (Figs. 124, 126) ••••••••••••••••••••••••••••••••••••••••• 23 Gills on abdominal segment 1 similar in structure to those on succeeding segments (Figs. 127-131); gills on segments 2-7 either forked or with margins fringed, not as above (Figs. 128-129, 131) 23(22) Gills on •••••••••••••••••••••••••••••••• abdominal --- (Fig. 125); gills 24 1 forked segment segments 2-7 on bilamellate with apical extensions produced into slender acute filaments (Fig. 126) .•••••••••••••••• Leptoph1ebia, p. 207 p. 203 abdominal segment 1 of single lamellae (Fig. 123); gills on segments 2-7 bilame11ate with apical extensions broadened (Fig. 124) Gills on linear .••••••. ••••••••••••••••••••••••••••• Choroterpes, |
