Mayfly Species Callibaetis montanus (Speckled Duns)

A brownish yellow species; cross veins of fore wing few in number; marginal intercalaries occur singly; male not known.

“Body discolored; notum testaceous, irrorated on each side with brown ochre, and traversed lengthwise by a median brown-ochreous stripe intersected by a light yellowish line” (Eaton). Legs “somewhat of a dull light Vandyke brownish-grey, stippled or irrorated minutely and densely in the femora with very light burnt umber brown”; tarsal joinings similar in color; distal joints of the tarsi darkened, claws black. Wings vitreous; cross veins of fore wing few in number, intercalaries single. Costal vitta light raw-umber brown in color, occupying the costal, subcostal and “next adjoining spaces,” and widened at the base of the wing; this band varies in intensity apically and in the basal costal space. Veins similar in color, except the basal costal cross veins, which are whitish. 6 or 7 cross veins before the bulla; beyond it “about 7 rudimentary and 7 well-defined simple and almost straight” cross veins. Tails white; joinings and basal joints yellowish.