ERYTHEMIS.—LEPTHEMIS. 339 
(Erythemis credula. 
Diplax credula, Hagen, Syn. Neur. N. Amer. p. 184 (1861) °. 
Trithemis credula, Kirby, Cat. Odon. p. 20 (1890) *. . 
Mesothemis credula, Calvert, Proc. Calif. Acad. Sci. (3), Zool. i. p. 408 (1899) *. 
According to my notes made in 1897 the formule for the post-triangular rows of the front wings of the types 
are: 3, 3, 3, 2, 2, 2, 2, (2) 3, 3, &e.; 2, 3, 3, 3, 2, 2, (2) 3, 3, &&. In some of the present material - 
the formula is: 3, 2, 2, 2, 2, 3, 3, &€., or even 2, 2, 2, 2, 2, 2, 3, 3, &e. 
Hab. Braz (M,C. Z.: 1 2), Minas Geraes !, Cachoeira [1 ¢, 1 2], Cuyaba [1 2], 
Uacarizal [2 ¢, 2 2], Corumba [1 ¢ ], Piedra Blanca [1 ¢ ] (H. H. Smith, Carn. Mus. 
Pittsh.), Rio Grande do Sul (v. Jhering, A. N. S.: 1 ¢); Wusr Inprus, St. Thomas }. 
Taken in April at Corumba and Piedra Blanca. | 
LEPTHEMIS. 
Lepthemis, Wagen, Syn. Neur. N. Amer. p. 160 (1861); Brauer, Verh. zool.-bot. Ges. Wien, xviii. 
pp. 368, 723 (1868); Kirby, Trans. Zool. Soc. Lond. xii. pp. 264, 802 (1889) ; Cat. Odon. 
p- 89 (1890). 
As here defined (anted, page 204), the genus includes but a single species. 
1. Lepthemis vesiculosa. 
Libellula vesiculosa, Fabricius, Syst. Ent. p. 421 (1775) *. 
Lepthemis vesiculosa, Hagen, Syn. Neur. N. Amer. p. 161 (1861)?; Proc. Bost. Soc. Nat. Hist. 
Xvill. pp. 73, 85 (1875) *; Kolbe, Archiv f. Naturg. liv. 1, p. 168 (1888) ‘; Kirby, Trans. Zool. 
Soc. Lond. xii. t. 57. fig. 1 (venation) (1889) ’; Ann. & Mag. Nat. Hist. (6) xiv. p. 268 (1894) °; 
(6) xix. p. 607 (1897) *; (7) iii, p. 866 (1899)*; Cockerell, Journ. Inst. Jamaica, i. p. 258 
(1893) °; Calvert, Proc. Calif. Acad. Sci. (3), Zool. i. p. 406 (1899); Prinzessin Therese, 
Berl. ent. Zeitschr. xlv. p. 262 (1900) "; Campos, Rev. Chilena Hist. Nat. iv. p. 47 (1900) **. 
Libellula acuta, Say, Journ. Acad. Nat. Sci. Philad. viii. p. 24 (1839) ™. 
The earlier literature on this species is cited by Hagen’. 
Comparison of individuals from widely separated localities has furnished the following data :— 
Altamira El Salado Babahoyo Port-au-Prince 
(186,39). | (86,39). (43,19). (43,49). 
Abdomen, go .......... (inmm.)| 40°5-44°5 | 40°5-43°5 42-44 39:5-4] 
” QD se seee cans ” 41-44 42-43 46 41-43 
Hind wing, d.......... ” 38-42 385-40 39-40 36°5-38 
” 99 Qc cece ewes ” 40-43 40-40°5 41 39-41°5 
Antecubitals, front wing, g ...... 14-17 14-16 14-16 14-17 
” yo Qe eee 15-16 14-16 13-14 15-17 
Do. most frequently, ¢ .......... 15 15 14,15 15, 16 
” 8 ” D ceecceeeee 16 14 eee 15, 16 
Antecubitals, hind wing, ¢ ...... 10-11 10.-11 10-11 10-11 
” re 10-11 10-11 9 10-12 
Do. most frequently, d .......... 10 11 10 11 
» 8 ” DO oveceeeueee 10,11. -}|-- 10° wees 11 
