34 MUSEO NACIONAL DE BUENOS AIEES. 



The nominal species of Ortliemis may be distinguislied by means 

 of tlie f oUowing table : 



Pterostigma long (6-7 mm). 



Nodus on all tlie wings bordered witli brown 



nodiplaga Karscli. 



Nodus not bordered witli brown. 



Labinm (nsnally) witliont a distinct, black, median band, 

 tips of wings not colorad as far as tlie pterostigma. 



ferruginea Fabr. 



Labium ^vitli a broad black median band, tips of wings 

 chestniít brown as far as tlie pterostigma 



sulphurata Hagen. 

 Pterostigma modérate (o mm). 



Dorsum of abdominal segments 4-7 predominantly blackish 

 witli yellow longitudinal lines on tlie mid- dorsal carina 

 and at eitlier lateral margin 



flavopicta Ivirby. 



Dorsum of abdominal segments 4-7 predominantly reddisli 

 with. a narrow black stripe either side or at apex only 



cultriformis n. sp. 



Of tliese I have not seen nodiplaga. 



Xodiplaga Karscli, Ent. Naclir. xvii, j). 267, 1891, was described 

 from a female (from Uruguay ?), probably just such. a one as Ha- 

 gen mentions (Stett. Ent. Zeit. xxix, p. 281). «Bei einem Weibclien 

 aus Montevideo sogar schwarzbraun an der Basis und ein kleiner 

 brauner Fleck um den Nodus aller Flügel.» Dr. Karscli mentions 

 as one distinction between nodiplaga and ferruginea that tlie for- 

 mer has five marginal cells in the discoidal (posttriangular) field 

 of the front wings, while the latter has 7-8. Individuáis of ferru- 

 ginea not infrequently have but 5, however, and some even 4. 



Ferruginea is the only species of the first group of whicli the 

 male is known. The form of its liamule [see Calvert, Proc. Calif. 

 Acad. Sci. (2) IV, pl. xvi, figs. 67, 69] is quite different from that 

 of the liamule of flavopicta and cultriformis, as its external branch, 

 instead of being rolled inward and its apex directed forward, is 

 directed outward and backward. 



Sulphurafa Hagen, Stett. Ent. Zeit. xxix, jj. 281, 1868, seems to 

 have escaped all the cataloguers, including Hagen himself . I could 

 not find the ty2:)e in the Museum of Comparative Zoology. The 



