Description of the final instar nymphs of seven species from Anacroneuria Klapálek (Plecoptera: Perlidae) in Costa Rica, and first record for an additional genus in Central America Author Gutiérrez-Fonseca, Pablo E. Author Springer, Monika text Zootaxa 2011 2965 16 38 journal article 10.5281/zenodo.278201 878ed78c-199d-465c-a2dc-e6fbdc65608a 1175-5326 278201 Perlesta sp. Figs. 25–26 Description. Body length : 10–11 mm . Head ( Fig. 25 ): three ocelli; brown forward of ocelli; pale m-line and pale anterior frontoclypeus, labrum with dense line of setae on anterior margin; occiput with sinuate, irregularly spaced transverse row of small spines, more or less complete behind ocelli. Pronotum : rectangular; brown with pale, well defined rugosities. Margins completely fringed with short thick bristles, somewhat variable in length. Meso- and Metanotum : pale midline; wing pads pale. Abdomen : segments with scattered dorsal spinules; branched anal gills present between cerci ( Fig. 26 ). FIGURES 25−26. Perlesta sp., 25. Head and thorax (pro, meso and meta notum); 26. Anal gills, apex of female abdomen, ventrally. Distribution. Costa Rica (genus distributed mainly in North America ). Local distribution ( Fig. 27 ): Known from a single location in the Central Valley of Costa Rica . Material examined. San José: Río Pará (La presa), Sta. Rosa de Moravia, 1600 m , 14.iii.1992 , S. Ramírez, 2 Ƥ. Comments. The nymphs herein described, were recently found during examination of the Aquatic Entomology collection at MZUCR. Several sampling trips to the original location were conducted in order to find more specimens; unfortunately, no further individuals could be found yet. This may be due to changes in the water quality and surrounding land use of the location during the past 15 years. The identification as Perlesta cannot be completely confirmed until adults have been collected.