522 CALIFORNIA ACADEMY OF SCIENCES. 



Dythemis Hagen. 



Hagen, Syn. Neur. N. A. p. 162, 1861. Brauer, Verb. Zool. Bot. 

 Ges. Wieu, xviii, pp. 368, 733, 1868. Kirby, Trans. Zool. Soc. 

 Loud, xii, p. 298, 1889. 



Synopsis of the North American species. 

 .3 rows of posttriaugular cells on tbe front wings. 



Abdomen slender (not more than 1.5 mm. wide at 5 in ,? ). 



Wings yellowish at base, to median cross-vein on front wings, to 

 the triangle on the hind wings; hind wings with dark streaks 

 in subcostal and median spaces; venation reddish; frous above 

 and vertex red to j-ellow. rufinervis Burm. 



Wings j-ellowish or brown at base to first anteciabital or less, ex- 

 treme apex brown to a width of 1 or 2 cells ( S ), hind wings 

 with no dark streaks; venation blackish; frons and vertex yel- 

 low to metallic bine; antehumeral stripe as iu velox. 



sterilis Hagen. 

 Wings brown at base to never more than half-way to first antecu- 

 bital, apex brown to a width of 4 cells or more ( ? ) ; frous and 

 vertex yellowish-green to brown; the pale antehumeral stripe 

 one-third to one-fourth as wide as the brown which separates it 

 from the luid-dorsal carina. velox Hag." 



AVings brownish at base, to internal triangle on front wings, to 

 discoidal triangle on hind wings, with darker streaks in the 

 subcostal spaces; frons and vertex reddish or yellowish; the 

 pale antehumeral stripe nearly as wide as the brown separating 

 it from the mid-dorsai carina. /»;/a.T Hag. 



Abdomen stout (2.5 mm. wide at 4). 



Denticles on the inferior side of the sup. app. S situated on a dis- 

 tinct projection; hamule at least twice as i^romiuent as genital 

 lobe. rnsscUa (Hag. MS.) u. sp. 



2 rows of posttriaugular cells on the front wings. 



inendax Hag., prcecox Hag., t Sallcei Selys, t tpertinax Hag. t 



28. Dythemis sterilis Hagen. PL xvi, figs. 52-55. 



Dy. s. Hagen, Syu. Neur. N. A. p. 317, 1861; Proc. Bost. Soc. N. 

 H. xviii, p. 87, 1875. LiheUula fessellata Eamb. Nevr. p. 89, 

 1842. 



*Doubtful if velox and sterilis are distinct. 



t Unknown to the writer. Since this paper was jireseuted for publica- 

 tion, Mr. W. F. Kirbj' has described a Dythemis multip%inctata (Ann. & 

 Mag. Nat. Hist., Oct., 1894) which has 3 rows of post-triangular cells, but 

 is also unknown to the writer; it inhabits St. Vincent, West Indies. 



