Mayfly Species Caenis amica (Angler's Curses)

Allied to Caenis diminuta, but the black apical mark on the middle and hind femora is a streak only, not a band.

Head fulvous; with black bands. Antennae white. Prothorax fulvous, banded with black; mesothorax brassy fulvous. Legs whitish, the fore legs much longer; cinereous, the femora obscurer; middle and hind femora with a black spot above upon the apex, this spot not continued downward to form a band, as in C. diminuta; on the outer side of the trochanter is a black streak. Wings semi-hyaline, whitish-grey, “the two costal veins black” (Hagen). Abdomen pale; tergites shaded with grey, the posterior margins and the sides marked with black. Tails white. Forceps short, much as in diminuta, but somewhat more curved than in the latter species, and the tips more finely pointed (see Pl. XXXIX).

Distinguished from C. diminuta by the lack of an entire black band on the hind femora, by the brighter brown of the mesonotum, and the black streak on the trochanter.

Described as C. simulans

Body length 3.5-4 mm, wing length 3.5-4 mm

A species with forceps of moderate length; mesonotum bronzy-brown; head blackish. See frontispiece.

Head entirely suffused with blackish above; eyes black, antennae pale. Pronotum pale yellowish; median area and antero-lateral margin strongly suffused with blackish; margins narrowly black. Mesonotum bronzy-brown, darker than in C. jocosa (now a synonym of Caenis latipennis); scutellum paler, faintly shaded with black. Metanotum pale shaded with black. Pleura bronzy-brown, paler around the bases of the legs; a few faint black streaks; a fine black line on the anterior margin. Sternum light yellowish. Fore legs with blackish shading at the bases; femora blackish, with a mere trace of a dark apical spot; tibiae and tarsi faintly smoky. Middle and hind legs pale yellowish; slight black dots and streaks on coxa and trochanter; dorso-apical black streak on femur fainter than in jocosa. Wings hyaline whitish; subcosta and radius purplish.

Abdominal tergites pale yellowish, shaded with black as in C. jocosa; black stigmatic dots on segments 1-7; a broken black mid-dorsal line on the first two or three tergites; tergites 8 and 9 deeper yellowish, with traces of a dark median dot on 9 and dark median longitudinal streaks on 10. Sternites pale; a pair of obliquely arranged dark dots on sternites 6-8; faint black lateral dashes on the basal sternites; and a small round brownish mid-ventral spot on each segment. Forceps faintly smoky; tails pale. Forceps of moderate length, distinctly curved, and slightly thicker than in C. jocosa (see Pl. XXXIX). This species, allied to C. jocosa, may be distinguished from it by the larger size, lack of black spots on the pronotum, presence of brownish mid-ventral spots, darker mesonotum and more curved forceps.

The species appears to be quite variable as to markings, dark forms having faint black lateral dashes on tergites 8-10; in some, the mid-ventral spots may be wanting. Western specimens which seem to belong here are somewhat larger than the eastern ones, with darker mesonotum and wider-spread blackish suffusion of the tergites.