Arenivaga bolliana (Saussure 1893)

Arenivaga bolliana (Saussure) (Plate IX, figures 3 to 5.)
1893. [Homoeogamia] bolliana Saussure, Rev. Suisse Zool., i, fasc. 2, p. 298. [cT, Texas.]
1904. Homoeogamia bolliana variety nigricans Caudell, Mus. Brooklyn Inst. A. & S.. Sci. Bull., i. p. 107. [o'; Esperanza Ranch, Brownsville, Texas.)
This Species is much the largest of the present genus. It is closely related to A. rehni, but may be readily separated by its much larger size, distinctive male genital characters, and different form, coloration and pronotal marking, when present, in the female.
The males exhibit much color variation; specimens with tegmina, wings and all but the broad pale cephalic margin of the pronotum, solid blackish, with a perceptible brownish suffusion, are before us from the Rio Grande valley (Brownsville, Eagle Pass). These have been named nigricans by Caudell. The condition is simply the maximum of intensive coloration found in the species, and every gradation to the normal type is found in the series before us. As we have already frequently observed, in the Orthoptera color variations are by no means worthy of varietal significance, and we consequently place nigricans in the synonymy here.
To the given male characters, we would add the following observations.
(Waco, Texas.) Interocular width slightly less than, to slightly more than, half the interocellar width. Pronotum with angles usually sharply rounded, sometimes quite broadly rounded, as in yl. erratica; this variation sometimes shown on one side and not on the other. Concealed genital hook proportionately very small when compared with that of rehni or erratica, shaft curving gently inward to near distal extremity, which is sharply curved inward, not enlarged, with apex sharp, directed proximad. Dextro-dorsal concealed genital plate, a large, flattened, smooth corneous finger, somewhat arcuate; dextro-ventral concealed genital plate, a large, irregular, corneous disk, strongly concave, with dorsal margins very broadly and strikingly shagreenous.
The adult female being hitherto unknown we here describe that
sex.
9 ; Carrizo Springs, Dimmit County, Texas. (A. Wadgymar.) [Hebard Collection.]
Description of Female. Very unlike male, apterous, size much larger, form suborbicular. Dorsal surface roughened and leathery, covered with very short, but stout, minute hairs, most of which are usually rubbed oft", except along the margins of the body. Pronotum broad, cei)halic margin evenly arcuate, at an angle of slightly over 90°, caudal margin weakly produced mesad, with sides broadly concave. Supra-anal plate transverse, trai)eziform. with distal angles rounded; mesal third of caudal margin truncate, with an indication of mesal emargination. Subgenital plate very large, roundly produced mesad.