Butterflies 217 



Outer margin of anterior wings with a solid black band ... 4. 

 Outer margin of anterior wings with a black or grayish band 



on which are yellow spots (common) Eurymus 



eurytheme eriphyle Edwards, female. 

 Outer margin of anterior wings with no distinct band, at most 



a blackish suffusion 8. 



4. The black band deeply excavated in the middle by the yellow . 5. 

 The band not excavated by the yellow 6. 



5. The yellow area with a black spot, the whole with the aspect 



of a dog's head in outline (a straggler from the south and 

 east, taken by Nash at Pueblo) . . Zerene caesonia Stoll. 

 The yellow very pale, and without a black spot; no black at 

 base of wing (a southern species, occasionally migrating 

 in great numbers, and temporarily common in Colorado, 



as far north as the mountains of Boulder County) 



Eurema mexicana Boisduval. 



6. Hind wing with a very broad blackish band, fading toward 



inner angle, (a straggler from the south, taken in Pueblo 



and Custer counties) . . . Eurema nicippe Cramer, female. 



Hind wing with narrow or evanescent yellow band, and anterior 



wings more pointed 7. 



7. Hind wing beneath pale greenish gray, with a light dot (common 



in the mountains) . . Eurymus alexandra Edwards, male. 

 Hind wing beneath sulphur yellow, with a silver spot bordered 



with reddish; a whitish spot on upper side of hind wings 



(common high in the mountains) Eurymus scuddcri 



Reakirt, male. 

 Hind wing beneath pale dull yellow or greenish yellow, with 



a discal spot; an orange spot on upper side of hind wings . . 



Eurymus eurytheme eriphyle Edwards. 



8. Larger, anterior wing about 30 mm. long, color distinctly 



yellow . . . Eurymus alexandra Edwards, female. 

 Smaller, anterior wing about 24 mm. long, color exceedingly 

 pale yellow or white . . Eurymus scudderi Reakirt, female. 



9. Anterior and posterior wings with broad black bands, the inner 



edge of the band on front wing strongly concave, forming 

 half a circle Eurema nicippe Cramer, male. 



