Campsurus decoloratus (Hagen)

(Figs. 44−46)

Palingenia decolorata Hagen 1861: 43.

Campsurus decoloratus Eaton 1883 −1888: 41.

Material. Two female adults from USA: Texas, Montgomery Co., San Jacinto river at US 59, near Kingwood, 17.viii.1997, N. A. Wiersema col.

Distribution. Mexico, Nicaragua, USA (http://www.entm.purdue.edu/mayfly/).

Diagnosis. Campsurus decoloratus can be separated from the other species of the genus by the following combination of characters: 1) pedestals and penes similar to C. violaceus, with pedestals elongate with outer corner slightly projected and penes slender, except that "thumb" is finger-like (figures 22−23 of Traver 1947); 2) female socket with straight transverse opening and with an anterior longitudinal rib (Figs. 45−46).

Female. Abdominal sternum VIII with a subquadrate single socket on the anteromedian area, the anterior furrow presents a thin medial rib ("r" in Fig. 46); in both female adults studied the groove (socket`s opening) appears obtruded by a subespherical aglutinated material ("?" in Fig. 46). The sternum VIII is completely covered by microtrichiae, except anteriorly and around the groove (Figs. 45−46).

Eggs (Fig. 44). Length, 188−237; width, 145−175. L/W ratio (N=5): 1.2−1.6. Hemispherical to ovate, with convex and concave sides as usual, capped pole broader, cap formed by>15 very long threads coiled around each other in a single stronger filament, chorionic surface covered by small punctures, except below the polar cap. Micropylar devices unknown.