Mayfly Species Labiobaetis frondalis

Abdominal tergites 2-6 of male imago deep brown; genitalia of the moffati type (now a synonym of Baetis tricaudatus); a deep excavation between the bases of the forceps, in which is a short spine.

Head and thorax deep shiny black. Brown markings on the pleural sutures. Legs pale yellowish brown. Wings hyaline. Stigmatic cross veins of the fore wing few in number, not anastomosing; no intercalaries in the first interspace. Hind wing long and narrow, the margins sub-parallel; third vein reduced to a mere trace. Costal projection greatly reduced (see fig. 163).

Abdominal tergites 2-6 deep brown; the anterior margins, especially laterally, pale and partially semi-translucent. Tergites 7-10 opaque, deep brown. Sternites pale dull cream-colored, the opaque apical ones with partial brown shading. Tails and forceps pale. The third joint of the forceps is long and narrow, the apical one very short and somewhat truncate. Between the bases of the forceps is a deep excavation, covered by a small triangular plate; a small spine is situated at the base of the excavation (see fig. 164).

This species is very similar to australis (now a synonym of Labiobaetis frondalis), from which species it may be distinguished by the greater amount of brown shading on the basal abdominal tergites, and the somewhat darker legs.

Described as B. australis

Body length 5 mm, wing length 4.5-5 mm

Abdominal tergites 2-6 of male imago purplish brown in lateral and posterior portions, the median and antero-lateral areas pale, semi-hyaline; genitalia of the moffati type (now a synonym of Baetis tricaudatus); an excavation between the bases of the forceps, in which is a small spine.

Turbinate eyes large, oval, orange in color. Thorax deep ruddy brown. Intersegmental areas of the pleura yellowish. Anterior portion of mesosternum lighter yellowish brown. Legs pale yellowish white. Wings hyaline, venation pale. 6-8 stigmatic cross veins in the fore wing, not anastomosing; only the two most apical ones of these reach the subcosta. Stigmatic area somewhat opaque. No intercalaries in the first interspace. Hind wing rather long and narrow; the third vein wanting or obsolescent, mere traces of it sometimes seen at the extreme base. A very short intercalary may be present between veins 1 and 2. Costal projection much reduced.

Tergites 2-6 largely pale, semi-hyaline, in the dorsal area, with faint submedian brownish streaks; antero-lateral margins also pale. Remainder of each tergite purplish brown. Tergites 7-10 opaque, reddish brown, with a purplish tinge. Sternites greyish white, semi-translucent. A continuous double blackish line outlines the tracheae on each side; from it arise branches which extend on to the tergites and sternites. In the holotype, the upper of these is the longer. Between the bases of the forceps is an excavation, at the base of which is a short spine, much as in frondalis (now a synonym of Labiobaetis frondalis); a penis-cover also is present, over this excavation (see fig. 164).

While close to B. frondalis, this species is slightly more slender, and the basal abdominal tergites exhibit more pale areas. The excavation between the bases of the forceps is also less deeply carved out.