388 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Forms with the hind margin of the pronotum angulate predominate east- 

 wardly, those with this margin rounded or very obtusangulate predominate 

 westwardly. The prevalent color of the base of the hind wings is pale 

 yellow or citron, but one species in the extreme east has this area generally 

 red, while in one found in the extreme west it is usually pale blue, though 

 both species have sometimes the normal yellow of the genus. 

 The species may be separated by the following table : — 



Table op the Species of Derotmema. 



A^. Smaller forms ; eyes very prominent ; tegmina distinctly tapering, with nearly 



straight costa, the intercalary vein subequidistant between median and ulnar veins; 



the more conspicuous markings of tegmina generally confined, and that narrowly 



and subequally, to the costal and inner edges. . . . [Derotmema proper] 



^1. Metnzona broad, the hind margin rounded, rarely feebly obtusangulate. 



c^. Dark band of wings normally broader than the metazona, reaching the 



margin posteriorly and percurrent, or broken only in the posterior axillary area. 



1. laticinctum. 



r2. Dark band of wings narrower than the metazona, not reaching the margin 



posteriorly and lacking almost throughout the axillary area. . 2. delicatulum. 



62. Metazona, even in female, no broader or scarcely broader than at eyes, the 



hind margin distinctly angulate. 



ci. Rugosities of metazona wholly irregular and not longitudinally pectinate ; 



dark band of wings relatively narrow, nowhere broader and generally narrower 



than length of pronotum, more or less narrowed in the posterior axillary area, 



and never occupying more but generally less than half the outer half of the 



wing ; base of wings pale blue or citron. 



c?i. Metazona rectangulate or feebly obtusangulate posteriorly (rarely in 



female considerably obtusangulate) ; costal margin of tegmina with dul' 



fuscous and ashen tints in no way conspicuously contrasted ; basal half of 



wings normally pale citron, occasionally subliyaline. . . 3. cupidineum. 



d". Metazona very obtusangulate posteriorly ; costal margin of tegmina 



with vivid contrasts of black and pallid, giving it an ornate appearance ; 



basal half of wings normally pale blue, occasionally pale citron. 



4. saussurearmm. 

 c^. Rugosities of metazona forming longitudinal ridges giving it a pectinate 

 appearance ; dark band of wings broad, subequal, much broader than length 

 of pronotum and occupying more than half the outer half of wing ; base of 



wings red or citron ' . 5. liajjdeni. 



A-. Larger forms ; eyes less prominent, especially in female ; tegmina of sub- 

 equal breadth, with arched costa, the intercalary vein closely approaching the 

 median and widely separated from the ulnar vein ; costal and inner edges of 

 tegmina not marked distinctively from the rest of the wing. . [Tmetodera.] 

 h^. Disk of pronotum relatively smooth, posteriorly obtusangulate ; tegmina 

 with contrasted markings on costal half, in large patches as in Conozoa. 



6. rileyanum. 



