388 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



22. Miathyria marcella Selys. 



Libellula marcella Selys, in Sagra, Hist. Cuba, Ins., 1857, p. 452. 

 Tramea marcella Hagen, Stett. Ent. Zeit., Bd. XXVIII, 1867, p. 227. 

 Miathyria marcella Kirbv, Cat. Odon., 1890, p. 4. 

 Tramea simplex Hagen, Syn. Neur. N. Am., 1861, p. 146, (teste Hagen). 



As compared with Hagen's description of 1867, the fol- 

 lowing differences exist: — 



In younger individuals of both sexes only the free margin of the labrum is 

 black, the remainder of the labrum ochre brown which becomes darker with 

 age. The dark brown basal band on the hind wings of the female does not 

 extend farther outwards than in the male, i. e., a very short distance beyond 

 the submedian cross-vein, 1 nor is the amount of surrounding yellow greater 

 than in the male. The venation is yellowish without a red tinge. 



Compared with Kirby' s statement of the generic characters of Miathyria 2 

 it is to be noted that some individuals show the inner (basal) side of the tri- 

 angle of the hind wings to be a little nearer the base of the wing than is the 

 arculus, instead of being in the prolongation of this latter. 



Dimensions: Abdomen, S 25-27 mm., $ 27 mm.; hind wing, S 32-34 

 mm., ? 33 mm. 



i $ 1 ? Tepic, Oct., 1894, Eisen and Vaslit. 

 2$ 2 ? " Nov., 1894, " " 



2 $ No locality or date. 



5* 3? 



The described species of Miathyria are very similar to 

 each other; the chief differences appear to be as follows: — 



1. Miathyria marcella Selys. 



Basal spot on the hind wings extending but little beyond the submedian 

 cross-vein (or rarely to the triangle in the female). Reticulation of a greater 

 number of cells than in simplex. Black spots on abdominal segments 5-10. 

 Size moderate (abdomen 23-27 mm., hind wing 30-34 mm.) Vulvar lamina 

 of female bilobed, lobes slender and a little longer than the interval separa- 

 ting them. 



1 I adopt henceforth the following changes in the nomenclatnre of the wings of Odon- 

 ata proposed by Baron de Selys (Ann. Soc. Ent. Belg., Tome XL, p. 85, March, 1896). Cos- 

 tal space between the costal and subcostal veins, subcostal space between the subcostal and 

 median veins, median space (formerly basilar space) between the median and submedian 

 veins; submedian space between the submedian and postcostal veins; in it is the normal 

 submedian cross-vein, which has been called postcostal cross-vein in the Agrionidae and 

 normal median cross-vein in the Libellulidee and ^schnidee; postcostal space between 

 the postcostal vein and the hind margin of the wings; it is wanting in those AgrionidEe 

 where the hind margin only commences beyond a petiolate base. 



2 Proc. Zool. Soc. Lond.,~Vol. XII, 1889, p. 269. 



