AKT. 2 EEVISION OF TRERHABDA NORTH OF MEXICO BLAKE 33 



In Derospidea the occipital spot may be present or absent, and the 

 head is glabrous. The three pronotal spots in TrlrJioibda are always 

 present; in Derospidea they are evident in one species, vestigial or 

 absent in two other species. When present, the median spot in 

 Derospidea tends to be Y-shaped. The elytra are only feebly 

 margined and are rounder and less parallel-sided than in Trlrhabda. 

 Derospidea is separated from Monocesta by having the fourth an- 

 tennal joint longer than the third and by the shape of the aedeagus. 

 The genus Monocesta as described by Clark was divided into two 

 subgroups, the first with the elytra postmedially dilated and the 

 second with the elytra more parallel. Weise has designated as the 

 type of the genus the first species of the first group {Monocesta im- 

 perialis Clark). Monocesta cyaneomaculata Jacoby, which I place 

 in the genus Derospidea^ was probably considered to belong in the 

 second group of Monocesta^ although the length of the antennal 

 joints should have excluded it. The aedeagus of Monocesta coryli 

 (pi. 2, fig. 27), the common United States species with postmedially 

 dilated elytra, is quite unlike that of Trirhdbda or Derospidea^ being 

 short and very broad with a short tip. 



1. DEROSPIDEA BREVICOLLIS (LeConte) 



Plate 2, Figure 23 



Trirhabda 'bremcollis LeConte, Proc. Acad. Nat. Sci. Philadelphia, vol. 17, p. 

 221, 1865. 



Description. — Robust, oblong, with very short prothorax, dull pale 

 yellow with reddish-brown darkening of antennae and tarsi, dark 

 occiptal spot and three often indistinct pronotal spots; elytra with 

 wide reddish-brown sutural and lateral vittae, usually united at apex. 

 Head pale, occiput shining, impunctate, glabrous, with coarse, shal- 

 low punctures about vertical fovea on front and between eyes, a 

 more or less evanescent reddish-brown spot on occiput extending 

 down vertex. Antennae with third and fifth joints subequal. Pro- 

 thorax considerably over twice as broad as long, with very arcuate 

 sides, often obtusely angulate at middle; median spot Y-shaped, 

 spots frequently evanescent; surface dimly alutaceous, with often 

 rather dense coarse punctures. Scutellum usually bicolored, apex 

 darkened by sutural vitta. Elytra oblong with feeble margin, 

 densely punctate throughout, more coarsely so at base, with fine 

 short pubescence; reddish-brown sutural vitta widest at base, but 

 scarcely attaining base of elytra and tapering to apex, at apex 

 uniting with wide lateral vitta, margin and epipleura often entirely 

 darkened. Body beneath pale with tibiae and tarsi darkened. 

 Length, 6.5 mm. to 9.5 mm. ; width, 3 mm. to 4.5 mm. 



Type locality. — "Abundant in Southern States, near sea coast, one 

 specimen from Kansas." 



