Cloudless Sulphur (Phoebis sennae)
Cloudless Sulphur (Phoebis sennae), female 
Fermilab, DuPage County, Illinois 
June 4, 2004

This is the only Cloudless Sulphur I have ever seen at Fermilab, a new species for the site.  It is a southern butterfly, which, like the much smaller Dainty Sulphur, occasionally disperses north but does not survive our winters.  

Cloudless Sulphur may be distinguished from the common Clouded and Orange Sulphurs in being larger and lacking the black border on the outer margin of the wings.  

Cloudless Sulphur (Phoebis sennae), female 
Fermilab, DuPage County, Illinois 
June 4, 2004 

Same individual as above.  I just happened to snap this photo as it took flight and caught the upperside of the wings.  Although not a good photo, it shows the absence of the black border.  

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