286 ORTHOPTERA. 



This insect most likely occurs further to the northward along the Isthmus, at least 

 into Southern Costa Rica *. 



* APTOCERAS, gen. nov. 



Related to Vilerna and Oaletodes, but differing from both of them in the more acuminate fastigium of the 

 vertex, the longer, somewhat nodulose antennae, the slightly shorter hind femora, and the narrower 

 tegmina. The most noticeable feature, however, in the single species at hand, is a cluster of small, 

 prominent, pearly granules or papillae on the metapleura and outer face of the hind femora. 



1. Aptoceras margaritatus, sp. n. 



A medium-sized locust, with sub-horizontal acuminate vertex and heavy nodulose antennae, narrow, somewhat 

 abbreviated tegmina and wings, and a cluster of small pearly spots on the meso- and metapleura, as well 

 as on the outer face of the hind femora. 



Head slightly wider than the front edge of the pronotum, the occiput short and slightly ascending ; eyes large, 

 prominent, a little longer than broad, separated above by a space equal to the width of the frontal costa 

 between the base of the antennae ; vertex somewhat ascending anteriorly, a little longer than its greatest 

 width, sulcate from a point in front of the occiput where the median carina of the latter terminates, this 

 sulcature bordered on the sides by a pair of heavy blunt carinae that diverge anteriorly to a point midway 

 between the front edge of the eyes and the apex of the fastigium and opposite lateral acuminate lobes, 

 these latter giving to the fastigium a tricuspidate appearance. Frontal costa very prominent between 

 the antennae, viewed laterally rounded ; broadly and quite deeply sulcate to the ocellus, below which 

 point it is nearly obliterated — being represented only by two or three pairs of elongate nodules arranged 

 down the middle of the face. Lateral or facial carinae more or less interrupted, but parallel. Pace 

 viewed in profile broadly concave. Clypeus and labrum moderately large, quadrilobate ; palpi very 

 heavy, the apical joint somewhat depressed, oval. Antennae 14- or 15-jointed, nearly as long as the 

 hind femora, very coarse and nodulose, the basal joints somewhat depressed. Pronotum rugose, a little 

 broader behind than in front, without lateral carinae, but furnished on the upper edge of the lateral lobes 

 with a rather large protuberance on each side between the hind and middle transverse sulci, a second 

 and smaller one in advance of the middle sulci and lower down, while a still smaller one is present on 

 each side of the disc a short distance back of the anterior edge ; the median carina is transformed into 

 a series of four elongate tubercles ; anterior edge very broadly rounded, hind margin also rounded, 

 but with the centre of the disc angularly produced, the angle slightly obtuse. Tegmina and wings 

 somewhat abbreviated, the former rather narrow, with prominent longitudinal veins and but few cross- 

 veins, their apices rounded ; wings infuscated. Hind femora slightly surpassing the tip of the abdomen, 

 moderately robust on the basal half, more slender beyond ; the carinae decidedly serrate, the upper edge 

 and outer face irregularly studded with tubercles, a few of those on middle of outer disc larger and pearl- 

 like in appearance, suggesting a possibility of luminosity at night. Hind tibiae six-spined externally. 

 Male-abdomen slender, the apex tapering, entire ; supra-anal plate elongate-triangular, the sides undulate, 

 slightly upturned, the disc provided with a series of dusky tubercles ; cerci pyramidal, hairy, the tip of 

 abdomen also rather strongly hirsute. Prosternum elongate, the spine located near its front edge, rather 

 robust, directed slightly to the rear. 



General colour dark wood-brown, varied on the head, pronotum, tegmina, and hind femora with dark brownish- 

 olive and black. Abdomen largely rufous, inside and lower sulcus, together with the hind tibiae and tarsi, 

 coral-red. Antennae with joints 9-11 white, 1-4 olivaceous, remainder dull black. Hind femora with 

 two oblique dusky bars across their outer face and upper edge. Metapleura and outer disc of hind femora 

 adorned with pearly tubercles, which are very conspicuous on the dark background. 



Length of body, d 1 > 19-20 ; of antennae 9-25, of pronotum 4-5, of tegmina 10, of hind femora 10'75 millim. 



Hob. Bbitish Guiana, Bartica, Demerara (R. J. Crew, in coll. L. Bruner). 



Two males. While it is only a surmise on the part of the present writer, it may prove to be a fact that 



