276 PEOCEEDINGS OF THE ACADEMY OF [PaRT II 



space four-fifths as wide as that between the sHghtly less prominent 

 ocelli, but fully two-thirds that between the antennal sockets. 

 Supra-anal plate half as long as distance between cereal bases, pro- 

 duced and nearly semicircular between these, subchitinous in dis- 

 tal portions. Subgenital plate short, rather decidedly convex, free 

 margin broadly and nearly evenly convex. 



Coloration as described for icano. The male type has the medio- 

 longitudinal paler streak of the pronotum even more suffused, 

 while the allotype has this marking nearly obliterated. In the male 

 type the coxae are less darkened and the tegmina are more evenly 

 suffused, while in the female allotype the coloration is darker. 

 These features are due to intensification and recession in coloration 

 and it would appear that in color features saussurei and icano are 

 similar. 



Length of body d" 10.2, 9 lli°«-10.7; length of pronotum d" 2.7, 

 9 3.1-2.9; width of pronotum d" 3.6, 9 4-3.8; length of tegmen cf 

 12, 9 12.3-11.8; width of tegmen cT 3.7, 9 3.9-3.7 mm. 



In addition to the type and allotype, a paratypic female, bear- 

 ing the same data, is before us. 



Ischnoptera icano new species. Plate XI, figures 11, 12 and 13. 



This species is very closely related to /. saussurei here described, 

 showing, however, distinctive features in the male genitalia. 



Of the small brown species of the genus, with pronotum margined 

 laterad and cephalad with buffy, five distinct species are before us 

 from the Argentine and Paraguay. Recent studies have shown 

 that an enormous number of forms belonging to this section of the 

 genus occur in tropical and subtropical America, frequently separ- 

 able on male genitalic characters alone, these parts, however, often 

 showing an intricacy of specialization of astounding degree. 



Type: d^ ; Border of Rio Salado, near Icano, Santiago del Estero, 

 Argentina. [Paris Museum.] 



Size small, form moderately slender. Interocular space moderate- 

 ly broad, four-fifths as wide as that between the large ocelli, nearly 

 half that between the antennal sockets. Flattened surfaces of 

 ocellar areas forming a rather blunt angle with the interocellar area. 

 Maxillary palpi short, fifth joint very slightly longer than third, the 

 fourth two-thirds as long as the third joint. Latero-caudal sulci 

 of pronotal disk very decided. Microscopic hairs scattered over 

 lateral portions of pronotum and proximal portions of tegmina. 

 Tegmina and wings fully developed, extending a short distance be- 

 yond apices of cerci. Wings with a moderately well-developed 

 intercalated triangle. Dorsal surface of abdomen specialized as 

 is characteristic of the genus, eighth tergite with caudal margin 



1°^ The measurements of the allotype are here given first. 



