GONTATEON". " 113 



description which follows, will be amply sufficient to distinguish the present genus. 

 It is confined in its distribution to the arid plains of Middle and Northern Mexico. 



1. Goniatron planum, sp. n. (Tab. I. figg. 20, 20, #., b, d *.) 



Medium-sized ; colour dark brownish-cinereous, but little variegated with lighter or darker markings. Head 

 not greatly enlarged, the occiput short, considerably elevated above the level of the pronotum, tbe vertex 

 between the eyes as wide as the shorter diameter of the latter, very gently sulcate and bounded on the 

 sides and front by distinct though blunt carinse, which meet anteriorly at a little less than a right 

 angle ; lateral foveolae visible from above, elongate triangular, more than twice as long as their basal 

 breadth ; eyes about the length of the cheeks below them, rather prominent, their front edge nearly 

 straight ; frontal costa very wide, its sides a little contracted above, coarsely punctate and but gently 

 sulcate in the vicinity of the ocellus ; antennae filiform, about as long as the hind femora. Pronotum 

 selliform, the sides higher than long ; the anterior lobe smooth, rounded above ; the transverse sulci 

 profound and continuous ; posterior lobe roughened, the disc flat, the shoulders well-defined and the 

 posterior edge slightly obtusangulate. Tegmina and wings ample, extending fully one-third of their 

 length beyond the tip of the abdomen ; the former rather heavily and profusely veined, the veins giving 

 them a leathery appearance, the wings yellowish-hyaline on the baeal half, becoming fuliginous apically, 

 where not only the veins but also the cells are more or less smoky. Hind femora only moderately robust 

 basally, slender apically, and not quite reaching the tip of the abdomen, which is acuminate. Hind tibiae 

 with eleven or twelve spines in the outer row. The abdomen differs from that of all other known forms 

 in having the dorsal portion on each side of the centre flattened, these fields being separated from 

 the sides by well-marked angles or ridges, the abdomen thus appearing tricarinate, hence the name 

 Goniatron. 



Length of body, c? , 23 ; of antennae 11*5, of pronotum 4-30, of tegmina 23, of hind femora 12 millim. 



Hab. Mexico, Comacho, Zacatecas (Bruner). 



The single specimen at hand, and which was obtained by the present writer in 

 November, has the lower sulcus of both hind femora provided with a rather conspi- 

 cuous transverse tooth or blunt spine, which is situated near the inner edge at a point 

 about one-fourth the length of this joint from its base. I do not believe that this 

 feature can be accidental, since two males of Ligurotettix also show the same feature, 

 but in a much less degree. 



included in the synoptical table separating the genera of the Tryxalinae {anted,, pp. 26-34). In order to 

 include the present genus, it is only necessary to modify the last paragraph of that table so as to make it read 

 as follows : — 



bb. Tegmina with a distinct intercalary vein, which is slender and intermediate 

 between the radial and ulnar veins. 

 c. Scapular area of S tegmina greatly dilated, hyaline and regularly 

 scalariform-veined. Abdomen unicarinate above. Hind tibiae with 



ten spines in the outer row Liotrotetiix, McNeill. 



cc. Scapular area of <$ tegmina not greatly dilated, the cross-veining less 

 regular, and this portion of the wing not greatly different from the 

 remainder. Abdomen tricarinate above. Hind tibiae with eleven or 

 twelve spines in the outer row Goniatron, Bruner. 



* Incorrectly marked $ on the Plate. 



biol. centr.-amek., Orthopt., Vol. II.. March 1905. Qq 



