Mayfly Species Macdunnoa persimplex

A small pale species; genitalia distinctive; it may be allied to Heptagenia elegantula (see fig. 95).

Eyes widely separated; vertex of head between eyes bright yellow, becoming pale creamy below antennae. Thorax creamy; yellowish tinges on pleura or bases of fore legs. Legs pale yellowish, shading into dirty whitish on tibiae and tarsi. Fore tibia smoky at apex; fore tarsus distinctly longer than tibia; basal tarsal joint normally about 1/3 the length of the second; second subequal to third, twice as long as fourth; fifth about as long as first. Considerable variation exists, in different specimens, however, as to the relative lengths of the fore tarsal joints. Wings hyaline; cross veins dark. 5 to 6 basal costal cross veins; stigmatic cross veins somewhat thicker than the others, but not as much so as in Anepeorus simplex (now a synonym of Spinadis simplex) which is superficially very similar to the present species.

Abdomen pale creamy; segments 1-7 hyaline, 8-10 opaque. Tails whitish. Apical margin of forceps base rather deeply excavated; penes slightly resemble those of H. elegantula on the one hand, and those of the H. lucidipennis (now a synonym of Nixe lucidipennis) group on the other. Forceps joints, however, as in the former species.