678 [December 



gin in front of the mesothorax ; pleura, scutellum and metathorax im- 

 maculate, the scutellum has occasionally two minute white spots, some- 

 times confluent, at tip ; posterior face of the metathorax flattened, the 

 posterior angles obtuse and scarcely developed ; tegulas black, with its 

 outer half white. Wings more or less stained with yellowish-fuscous, 

 in one specimen rather strongly tinged with fuliginous and the tip of 

 the marginal cell darker; nervures yellowish-ferruginous. Legs black, 

 shaped as in zonalis 9 ; the extreme tips of the coxae and femora some- 

 times whitish ; tibiae pale yellowish, with a fusco-ferruginous stain on 

 the apical half beneath; tarsi pale ferruginous. Abdomen robust, deep 

 black, with a slight gloss ; all the segments above, except the terminal 

 one, with a more or less narrow white band on the apical margin, some- 

 times entire, sometimes slightly interrupted on the middle, sometimes 

 finely serrated anteriorly and often more or less emarginate on each 

 side anteriorly, especially those on the fourth and fifth segments; apical 

 segment entirely black, broadly rounded at tip; beneath deep black, 

 immaculate. A single specimen varies in the clypeus having a short, 

 longitudinal white line on the disk, a minute white dot on the pleura 

 immediately beneath the anterior wing, a minute white dot on each side 

 of the apical segment of the abdomen above, and the third segment 

 beneath has a row of four white dots on the apical margin. Length 

 5 — 6 lines ; expanse of wings 9 — 10 lines. 



Hab. — Rocky Mountains, Colorado Territory. 18 9 specimens; % 

 unknown. 



This species is distinguished at once from M. zonalis by its much 

 more robust form, and the nearly pure white markings. It was col- 

 lected by Mr. Ridings on the same plant and in the same locality that 

 he found M. zonalis. He was unable to discover the % after a long 

 and diligent search. 



