1921] NATURAL SCIENCES OF PHILADELPHIA. 273 



the small species of the genus, particularly distinctive in havinjs; the 

 styles of the male subgenital plate simple, straight, cylindrical and 

 virtually unarmed. 



As we have elsewhere noted, a great number of small species of 

 the genus exist, divisible by color features and pattern into only 

 a few very large groups. The specialization of the male genitalia 

 is distinctive in these species, often showing an astonishingly in- 

 tricate development. Females are , however, exceedingly difficult 

 ot separate and should never be recorded as this or that species 

 without the aid of some definite sex correlation. 



Type: d^ ; Las Garzas,^^ Rio Las Garzas, Santa Fe, Argentina. 

 [Paris Museum.] 



Size sm ill, smaller than in saussurei or icano, form moderately 

 slender. Interocular space very broad, slightly wider than that 

 between the large ocelli, four-fifths as wide as that between the 

 antennal sockets. Ocellar areas, maxillary palpi, few microscopic 

 hairs of pronotum and tegmina, tegmina, wings and specialization 

 of dorsal surface of abdomen as described for icano on page 276. 

 Eighth tergite with caudal margin not as decidedly concave as in 

 that species. Supra-anal plate nearly symmetrical, length approxi- 

 mately half basal width, surface very weakly convex in all but small 

 latero-proximal portions, lateral margins straight and moderately 

 convergent in brief portions to beyond cereal bases, thence less 

 strongly convergent and feebly convex to distal portions, this polr- 

 tion broadly and weakly bilobate, the dextral slightly broader than 

 the sinistral lobe, the median emargination thus formed broadly 

 obtuse-angulate and rounded. Ventral surface of supra-anal plate 

 with a small but heavy conical projection, slightly mesad of the 

 base of the sinistral cercus; with a large, heavy tuft of agglutinated, 

 chaetiform spines, which curve sinistrad, situated a brief distance 

 before the base of the distal emargination, and with the dextral 

 margin somewhat thickened ventro-proximad and armed with 

 chaetiform spines. Paired plate beneath supra-anal plate large. ^^ 

 Subgenital plate rather decidedly convex laterad; sinistral margin 

 nearly transverse to median production, a brief distance before 

 that supplied with an elongate, slender, straight, cylindrical style, 

 over four times as long as broad; dextral margin moderately oblique 

 produced, broadly convex to median production, that area very 

 small, about twice as broad as long, with margin broadly convex 

 sinistrad to the rectangular, sharply rounded dextral angle, before 

 which is situated the dextral style, slightly inset, but in every other 

 way similar to the sinistral style. "« These styles are virtually un- 



3^ Twenty five kilometers west of Ocampo. 

 ^^ In greater part hidden in the specimens at hand. 



^^ In the paratype these styles average even longer, fully five times as long as 

 board. * 



