Mayfly Species Neochoroterpes oklahoma

This is a very dark brown species, with grey-brown mottled abdomen. Head dark brown above with paler brown antennae. Thorax shining blackish brown above, with a very narrow pale line in the notal furrow, and a wider pale strip just beneath it before the wing roots. Sides and sterna also dark brown. Legs brown and dull yellow, with whitish tarsi. The brown about equals the yellow in extent, is very diffuse, showing little cross-banding, but is darker on the longitudinal carinae. Wings subhyaline, darker in the subcostal space, and with brown longitudinal veins in the costal half, behind which they are transparent, as are all cross veins.

Abdomen greyish brown, paler beneath, darker on the end segments, and with a pretty pattern on segments 2 to 9 of large pale middorsal V marks through which runs the narrow middorsal pale line conjoining them. On the lateral margin of segments 2 to 8 there is a minute white spot surrounded in front by a blackish crescent. Tails greyish, the segments paler toward the base of each, obscurely darkened on the joinings, and so, faintly ringed. Sides of the 9th sternite marked with an elongate brown triangle; remainder white, including the forceps. Penes brown (see fig. 140).