Epeorus vitreus

Webb, J. M. & Mccafferty, W. P., 2006, Contribution to the taxonomy of Eastern North American Epeorus Eaton (Ephemeroptera: Heptageniidae), Zootaxa 1128, pp. 57-64 : 62-63

Key to known larvae of the eastern north American vitreus species group

1. Lamellae of first pair of gills each with large anterior expansion, usually meeting or nearly meeting ventrally ( Fig. 11 ) [lamellae of gills 1 of E. namatus only slightly

expanded anteriorly ( Fig. 12 )]; subdorsal setae on femora pectinate; maxillae with more than one seta at base of apical tooth complex ( Fig. 14 ); dorsal projection at apex of femora blunt; lamellae of gills 7 usually with longitudinal fold................................. ................................................................................................ E. pleuralis species group ­ Lamellae of first pair of gills cordate, not expanded anteriorly ( Fig. 9 ); subdorsal setae of femora simple; maxillae with single fimbriate seta at base of apical tooth complex; dorsal projection at apices of femora blunt or sharp; lamellae of gills 7 usually without longitudinal fold .................................................................... E. vitreus species group, 2

2. Dorsal (outer) posterolateral projections of abdomen distinctly longer than ventral projections ( Fig. 13 ) .............................................................................................. E. vitreus

­ Dorsal (outer) posterolateral projections of abdomen subequal to or only slightly longer than ventral posterolateral projections ( Fig. 8 ) ................................................. 3

3. Abdominal terga each with small but distinct median protuberance on posterior margin, increasing in size posteriorly; head distinctly wider anteriorly ( Fig. 15 ) and nearly uniform brown; gills 7 with longitudinal fold .................................................. E. dispar

­ Abdominal terga without posterior median protuberances or terga 2 or 3–7 each with small median protuberance, decreasing in size posteriorly; head subrectangular ( Fig. 1 ), with four large pale markings; gills 7 without longitudinal fold ............................ 4

4. Dorsal projection at apex of hind femur sharply pointed ( Fig. 16 ); pronotum with small pair of tubercles ( Fig. 17 ); mature larvae>8.0 mm long ................ E. subpallidus

­ Dorsal projection at apex of hind femur bluntly pointed ( Fig. 7 ); pronotum without pair of small tubercles; mature larvae 6.0–8.0 mm long ............................. E. punctatus

Figures

FIGURES 11 – 17. 11, Epeorus pleuralis, Gill 1, lamella; 12, Epeorus namatus, gill 1, lamella; 13, Epeorus vitreus, abdominal segment 7; 14, Epeorus namatus, maxilla; 15, Epeorus dispar, head capsule; 16, Epeorus subpallidus, apex of hind femur; 17, Epeorus subpallidus, pronotum, dorsal view.

FIGURES 1 – 10. Epeorus punctatus. 1, head capsule; 2, labrum; a: dorsal, b: ventral; 3, left mandible; 4, right mandible; 5, maxilla; 6, hind femur; 7, apex of hind femur; 8, abdominal segment 7; 9, Gill 1, lamella; 10, gill 6, lamella.