THYEIPTiLON.— SISANTUM. 69 



foveolae subobsolete. Eyes prominent, bulging, not much pointed above, and considerably shorter than 

 that portion of the cheeks below them. Antennae with the basal joints flattened and subensiform, about 

 as long as ( $ ), or considerably longer than ( J ), the combined length of the head and pronotum. Face 

 very oblique, long and straight when viewed from the side. Pronotum short, somewhat compressed, the 

 sides higher than long, the lower edges on the anterior half obliquely truncate ; lateral carinas parallel 

 or nearly so on the anterior lobe, greatly divergent on the posterior ; last transverse sulcus profound and 

 situated distinctly behind the middle; anterior margin of the disc somewhat rounded, the posterior 

 broadly angulate. Tegmina and wings complete, extending a little beyond the tip of the abdomen, even 

 in the female ; the former with the apex obliquely truncate, the costal or scapular edge somewhat dilated, 

 in both sexes, and without any traces of an intercalary vein. "Wings provided on the costal area with a 

 series of large, quadrate, window-like cells, that shine like highly polished glass, hence the name 

 " Thyriptilon." Hind femora heavy on the basal half, slender apically, as long as ( $ ) or longer ( c? ) 

 than the abdomen. Hind tibiae provided with 11-13 spines in the outer row. 



l. Thyriptilon vitripenne, sp. n. 



Uniformly dull brown, with indications of a darker streak along the upper edges of the sides of the pronotum, 

 and sometimes with the tegmina evenly and rather profusely flecked with darker brown dots. Wings 

 highly polished, very slightly tinged with yellow and becoming faintly clouded at the apex ; the anterior 

 border, especially in advance of the series of large quadrate cells, thickened and dark-coloured — possibly 

 a stridulating device. Hind femora with the lower portion of the inner face on the basal half and lower 

 outer edge black. 



Length of body, 6 17-18, $ 28-30 ; of antennae, d 9, $ 8 ; of pronotum, <S 3*7, $ 4-85-5-15 ; of tegmina, 

 <5 18, $ 23-24; of hind femora, <J ]2, $ 16 millim. 



Hah. Mexico, Valladolid in Yucatan (Gaumer). 

 Fourteen males and six females. 



SISANTUM, gen. nov. 



Having the general appearance of both Orphulella and Thyriptilon, but differing considerably from each in 

 a number of details. 



Occiput ascending, eyes a trifle prominent, broadly oval, about as long as the portion of the cheeks below them, 

 the vertex gently depressed in front, sides of the f astigium straight, meeting in a right angle ( $ ) or less 

 ( 3 ), and followed internally by a rather deep groove ; lateral foveolae discernible as elongate depressions, 

 slightly broadest next to the eyes ; frontal costa percurrent. Antennae filiform, rather longer than the 

 head and pronotum combined. Pronotum gently expanding posteriorly, the lateral carinae less prominent 

 than the median but of equal prominence throughout, more or less divergent, especially on the metazona ; 

 prozona and metazona of about equal length, the lateral lobes deeper than long. Tegmina usually broadly 

 rounded at the apex, but sometimes showing some indication of being obliquely truncate above ; rather 

 broad, and membranous to a greater extent than usual on the apical half or two-thirds. Wings hyaline, 

 with their anterior edge re-enforced and provided with the usual large regular cells just behind the costa. 

 Hind femora heavy basally, slender apically ; the tibiae provided with 13 spines in the outer row. 



1. Sisantum notochloris, sp. n. (Tab. I. figg. 11, 11 a, $ .) 



This insect, which is the type of the genus, is characterized by having the top of the head, the disc of the 

 pronotum, and the dorsal field of the tegmina uniformly grass-green. At first glance, save for its 

 somewhat smaller size and filiform antennae, it might be mistaken for the male of Truxalis brevicornis 

 (Linn.). 



Head about as wide as ( c? ), or a little wider than ( $ ), the front edge of the pronotum ; vertex between the 

 eyes about two-thirds ( <$ ) or three-fourths (?) as broad as their shortest diameter, projecting anteriorly 

 for a distance about equal to or slightly less than its width posteriorly. Frontal costa rather broad, 



