Mayfly Species Labiobaetis ephippiatus

Abdominal tergites 2-6 of male imago pale yellowish white, semi-hyaline, marked with purplish red; hind wing two-veined, no costal projection; genitalia of the modified moffati type (now a synonym of Baetis tricaudatus).

Head light reddish brown; antennae yellowish, a red-brown ring at apex of basal joint. Turbinate eyes large for size of insect, on high stalks; stalk yellowish flushed with pink, upper surface pale orange, in alcoholic specimens. Pronotum light red-brown. Mesonotum quite dark red-brown; median suture and margins of scutellum blackish; a pale line anterior to the wing root. Intersegmental areas of pleura yellowish red, remainder red-brown. Metanotum chestnut brown. Sternum red-brown, median area paler. Legs pale yellowish white; tarsi not clouded. In a few specimens, a narrow blackish ring near apex of femur, and a black hair-line the length of that joint. Wings hyaline, venation pale. A whitish cloud in stigmatic area of fore wing; 7-8 cross veins, aslant, often incomplete near subcosta; granulations present. Marginal intercalaries well developed; none in first interspace; those of second space short. Hind wing with no costal projection; small and narrow, leaf-like; two veins only (see fig. 163).

Abdominal segments 2-6 semi-hyaline, whitish with a faint yellowish tinge. Tergites 2 and 5 much marked with purplish red; geminate submedian streaks, and all except the anterior and lateral margins variably shaded with this color, in irregular saddle-shaped pattern. Often geminate streaks are present also on tergites 3, 4 and 6, with traces also of lateral shading. Posterior margins narrowly but distinctly purplish red (on tergites 2-4, these dark rings may be obsolescent). Spiracular line and spiracles outlined prominently by a geminate black line, with lateral branches on each segment. Segments 7-10 opaque; tergites reddish brown, 8 deeper in color than others, tinged with purplish; posterior margins darker. Sternites paler, yellowish; 8 usually almost wholly light reddish brown with purplish tinge; lateral margins of 9 brownish. Tails and forceps yellowish white. Genitalia of the modified moffati type (now a synonym of Baetis tricaudatus); a rounded projection on inner apical margin of basal forceps joint; second joint swollen somewhat, near middle of inner margin; distal joint short. A truncate penis-cover is present between the basal joints (see fig. 164).