Mayfly Species Ameletus ludens (Brown Duns)

A rather small clear-winged brownish species, with distinct blackish oval ganglionic marks on the venter of the abdomen.

Head of male blackish. Eyes of male honey-colored in life. Thorax reddish brown. Mesonotum yellowish to olive brown; scutellum reddish yellow; the area just anterior to it cream colored, and a pale cream colored patch on each lateral margin. Metanotal scutellum rather similarly marked. Anterior to the wing root is a pale cream colored area varied with a reddish tinge; similar patches on the pleura. Sternum blackish in the male. Fore legs dark reddish brown; middle and hind legs brown. Wings hyaline, veins blackish brown. Stigmatic cross veins tend to anastomose. Abdomen of male semi-translucent except on the apical segments; pale yellowish brown above, paler beneath. Basal and apical segments washed with reddish brown. Rather wide dark brown bands on the posterior margins; postero-lateral angles dark brown. Sternites paler than tergites; apical sternites opaque reddish brown. Each ganglionic area is marked by a blackish oval spot, having a distinct black line through the center. Posterior margins, behind the dark bands, narrowly pale. Margin of pleural fold pale. Apical tergites and sternites often marked with creamy white areas which are tinged with red. Basal sternites pale, semi-translucent; apical sternite opaque. Forceps blackish, tawny at the base. The long joint of the forceps is swollen basally and distally. The penes are long and slender, slightly divergent distally (see fig. 116). Tails dark reddish brown basally, becoming somewhat paler distally. Joinings darker.

Head of female dark brown. Pronotum with paler median and lateral areas. Sternum dark reddish brown. Abdomen reddish brown dorsally, paler ventrally. The subanal plate of the female is rather long, extending almost to the end of the tenth segment.

The mature nymph is dark reddish brown with cream colored markings. Legs pale, banded with brown. Abdominal tergites 8-10 very dark brown; basal and middle tergites varied with indistinct paler median, lateral and posterior markings. Dark brown oblique submedian marks present. Postero-lateral spines on segments 4-9, very small on 4 and 5. Ventrally, three very wide dark reddish brown bands occupy most of each sternite. These bands coalesce completely on sternites 8 and 9, and are more or less diffuse on the other sternites. No distinct pale streak separates the lateral dark line from the lateral margin of the sternite. Tails with the usual dark bands. This species is of particular interest in that it ordinarily reproduces parthenogenetically.