Caenis chamie Alba-Tercedor & Mosquera, 1999 (Figs. 10E–F)

Caenis chamie Alba-Tercedor & Mosquera, 1999: 61; Lima et al. 2015a: 3; Lima & Boldrini 2016: 3; Nascimento et al. 2022: 117.

Distribution. Colombia. Brazil: states of Goiás, Pernambuco, Roraima, Piauí. New record: Rondônia State.

Material examined. 10 ♁ imagos (light trap), Brazil, Rondônia State, Rolim de Moura municipality, Waterfall, road 192 south, S11°50’34.8”, W61°42’50.3”, 21.viii.2022, Nascimento, S. R .S., Cruz, P. V., Lima, C. R . T . cols. (INPA).

Comments. Caenis chamie can be characterized by the straight hind margin of penis, genital sclerites sclerotized and discernible, and styliger plate projected, covering the penis (adapted from Alba-Tercedor & Mosquera 1999). Specimens from Rondônia were compared with photographs of the holotype of male imago. Small variations in the shape of the forceps were observed, with some specimens presenting forceps longer and slender, with subapical constriction. Variations on the forceps were also previously commented on by Alba-Tercedor & Mosquera (1999). The most noticeable variation is the lateral sclerite, with evident sclerotization, tape format and broad base; this structure is barely visible in the holotype of C. chamie .