Descriptions of three new species of Odonata from Brazil Author Costa, Janira M. Departamento de Entomologia, Museu Nacional, Universidade Federal do Rio de Janeiro (UFRJ) BR 20940 - 040, Quinta da Boa Vista, São Cristóvão, Rio de Janeiro, RJ, Brasil. E-mail: jcosta @ globo. com. br Author De Souza, Luiz Onofre I. Departamento de Biologia / CCBS, Universidade Federal de Mato Grosso do Sul (UFMS) BR 79070 - 900, Cidade Universitária s / n, Campo Grande, MS, Brasil. E-mail: loisouza @ nin. ufms. br Author Muzón, Javier Instituto de Limnologia “ Dr. Raül A. Ringuelet ”, La Plata, Argentina. E-mail: muzon @ ilpla. edu. ar text Zootaxa 2006 2006-09-14 1314 53 68 journal article 10.11646/zootaxa.1314.1.4 2910e4d2-fd49-4368-b389-202015b74ce2 1175­5326 173923 Key to adult males of the species of Perithemis known from Brazil (Modified and updated version of keys from Needhan at al . (2000) and von Ellenrieder and Muzón (1999)) 1. Tip of hamuli almost at level of ventral margin ( Fig. 44 ) ............................................. 2 1’. Tip of hamuli at nearly 0.40 from ventral margin ......................................................... 6 2. Pterothorax with two lateral dark strips well defined ( Fig. 45 ); genital ligula with length of sclerotized distal portion of fourth segment less than half the length of the segment, margins parallel basal portion subquatrate ............................................ P. lais 2’. Pterothorax with one well defined lateral dark stripe, the second lateral stripe poorly defined. Vesica spermalis with length of sclerotized distal portion of fourth segment half the length of that segment, margins not parallel basal portion subquatrate or trapezoidal .................................................................................................................... 3 3. Posterior region of head black; first segment of vesica spermalis rounded or trapezoidal.......................................................................................................................................4 3’. Posterior region of head dark brown or reddish; first segment of vesica spermalis sub­quadrate (Figs. 46–47) ............................................................................... P. icteroptera 4. Abdomen without narrow oblique dark stripes on segments 4–9 ................................ 5 4’. Abdomen with complete blackish longitudinal bands ( Fig. 48 ) ......................... P. thais 5. Wings rich golden yellow .............................................................................. P. cornelia 5’. Wings red­orange .............................................................................................. P. rubita 6. All triangles and subtriangles free ( Fig. 49 ); first segment of vesica spermalis trapezoidal ( Figs. 50–51 ) ............................................................................................. P. mooma 6’. At least one of triangles and subtriangles crossed. First segment of vesica spermalis ovoid or rounded...........................................................................................................7 7. Legs dark brown; subtriangles in forewing with two or three cells; abdomen robust .... ............................................................................................................................. P. bella 7’. Legs ochraceous yellow. Abdomen slender .................................................................. 8 8. Triangles in both wings free, subtriangles in forewing with two cells; wings broad ( sensu Ris, 1930 ); first segment of vesica spermalis ovoid ( Figs. 52–53 ) ....... P. electra 8’. Triangles in both wings crossed with three cells; wing narrow ( sensu Ris, 1930 ); first segment of vesica spermalis rounded ( Figs. 37–38 ) .................................... P. capixaba