68 THE AMERICAN CHARACIDAE. 



n. No caudal spot; a vertical humeral spot. A. 28-30. 



16. megalops Eigenmann. 

 nn. A median caudal spot; no humeral spot. A. 26. 



17. shideleri Eigenmann. 

 kkk. Upper caudal lobe with an oblique black band, continued downward 



across the caudal peduncle and along the basal portion of the anal. 

 A. 27-28, scales 5.5-32 or 33-3.5; head 3.4-3.75; depth 2.25-3.25. 

 Longitudinal extent of premaxillary insignificant. 



18. costae (Steindachner). 

 aaa Depth usually more than 2.75 in the length (2.6 in M. dichroura, M. lata, and gravid M. colletli), 



anal less than 28 in all but exceptional specimens of M . dichroura and M. lata, 

 o. Base of caudal without definite spot or band. 



p. Premaxillary very short; maxillary with its anterior margin 

 very convex. Caudal lobes black at the tips, or with a black 

 band across them, their tips white; base of caudal pale; 

 depth usually 3(2.75); A. 25-27 rarely 28; lat. line 36 or 37 

 (rarely 34, 35, or 39); gill-rakers one third to one half the 



length of the eye 19. dichroura (Kner). 



pp. Anterior margin of maxillary not sharply and evenly curved 

 premaxillary longer than under p, the mouth strong. 

 q. Tips of caudal lobes black or a black band across the lobes. 

 r. A. 25; scales 5-35-3.5; depth 3.1-3.75. 



20. intermedia Eigenmann. 

 qq. Lobes of caudal without well-defined cross-band, 

 s. Base of anal without a black line. 

 t. Base of upper caudal lobe yellow or orange, this fol- 

 lowed by black which fades toward the tip with water 

 markings. 

 u. Depth 3-3.5; A. 24 (21-27). 



21. lepidura lepidura (Kner) . 

 uu. Depth 2.6; A. 26 (25-28); lateral line 33 or 34, 

 middle caudal rays faintly colored. 



22. lepidura lata Eigenmann. 

 It. Upper caudal lobe not black. 



v. Depth 3; A. 23 or 24; lateral line 31-33; pectorals 

 not reaching ventrals; upper caudal lobe and 

 sometimes the distal part of the other rays 



dusky 23. lepidura icae Eigenmann. 



w. Depth 3.4; A. 24; lateral line 37; pectorals not 

 reaching ventrals; caudal lobes plain. 



24. lepidura hasemani Eigenmann. 

 vw. JDepth 4; A. 21-23; lateral line 35-36; pectorals 



to ventrals; usually the middle caudal rays 

 and distal part of all the other rays dusky. 



25. lepidura gracilirna Eigenmann. 

 ss. Anal with a dark (zigzag) line along its base; silvery 



lateral line very narrow, bordered with dark above, 

 no caudal spot; upper part of cheek and opercle with 

 numerous chromatophores. 



