ASHNA.—GYNACANTHA. 189 
“P. Br.” and “4. erythroneura” in Selys’s hand), Rio Grande do Sul (H. H. Smith, 
M. C. Z.: 1 2%); Areentine Repusiic, Goya, Corrientes (Perren 1); Paraauay, 
Sapucay (W. 7. Foster, U. S. N. M.: 17 6,3 2). 
The two males from Atoyac were collected in April and May. 
GYNACANTHA. 
Gynacantha, Rambur, Névr. p. 209 (1842)*; Selys, in Sagra’s Hist. Cuba, Ins. p. 459 (1857) 73 
Hagen, Syn. Neur. N. Am. p. 131 (1861) *; Karsch, Ent. Nachy. xvii. pp. 273, 275, 280 
(1891)‘; Berl. ent. Zeitschr. xxxviii. p. 28 (1893)°; McLachlan, Trans. Ent. Soc. Lond. 
1898, p. 439°; Kriiger, Stett. ent. Zeit. 1898, p. 275"; Forster, Termes. Fuzetek, xxi. 
p. 91 (1900) *. 
Triacanthagyna, Selys, Bull. Acad. Belg. (3) v. p. 745 (1883) °. 
Gynacantha, Kirby, Cat. Odon. p. 94 (1890) *°; Ann. & Mag. Nat. Hist. (6) xix. p. 614 (1897) *; 
Selys, l.c. p. 745 (1883) ”. 
Acanthagyna, Kirby, Cat. Odon. p. 94 (1890) **. 
Karschia, Forster, Termes. Fiizetek, xxiii. p. 91 (1900) *; Karsch, Abh. Senck. naturfor. Ges. xxv. 
p. 213 (1900) *. 
Not having critically studied the Gynacanthas of the Old World, I have, pro- 
visionally, followed Prof. Karsch 415 in recognizing but one genus for the following 
forms. Some of the venational characters which are here employed for the first time 
in separating species have yet to be investigated in those of the other hemisphere. 
I cannot, however, regard Mr. Kirby’s argument! for his choice of the type of 
Gynacantha as valid ; I consider the type 12 to be nervosa, Rambur *. 
This genus is circumtropical. 
Synopsis of the Species of Mexico and Central America. 
A. Basal subcostal cross-veins absent. 
B. Two rows of cells between principal and nodal sectors beginning under 
the pterostigma, anal loop of the hind wings at its nearest point to the 
hind margin separated therefrom by two rows of cells ; inferior appen- 
dage of the male one-fourth to three-tenths as long as the superiors, 
ventral process of tenth abdominal segment of female three-pronged. 
C. Frons with a black T-spot above; legs reddish, tending to black at the 
knees ; abdomen constricted at segment 3, less so in the female; . 
maximum number of rows of cells on the hind wings between short 
sector and supplementary sector next below, four; anal triangle of the 
male 3-celled. Abdomen (excl. apps.), ¢ 37°5-47, 3 45-48°5 ; 
apps., ¢ 5-7, 2 6°5-9; hind wing, ¢ 35-44, ¢ 42-47; costal edge of 
pterostigma, front wing, 3-4 mm. . - - . ee ee ee ee A. trifida. 
* After writing the above, I notice the similar position taken by Mr. McLachlan (Ann. & Mag. Nat. Hist. 
[6] xvii. p. 411, footnote, 1896). 
