from the April 18, 2010 Newsletter issued from
Hacienda Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO
A white-dotted butterfly zipped across the trail and landed on a rock, spreading his wings against the early-morning sun. He was a little similar to the Tulcis Crescent that was so abundant awhile back, but different. I snapped his picture, which you can see above.
As usual I sent the picture to butterfly-ID volunteer Bea in Ontario and this time instead of replying with a single choice she gave me three. After reviewing her links for each of the three I understood, for I couldn't see the differences between them. If you'd like to try -- remembering that relative AMOUNTS of light and dark pigmentation are far less important than spot DISTRIBUTION -- here are links to each of the three names Bea sent:
Pyrgus albescens (White Checkered-Skipper) http://www.mariposasmexicanas.com/pyrgus_albescens.htm
Pyrgus oileus (Tropical Checkered-Skipper) http://www.mariposasmexicanas.com/pyrgus_oileus.htm
Pyrgus philetas (Desert Checkered-Skipper) http://www.mariposasmexicanas.com/pyrgus_philetas.htm
On the Internet a technical paper acknowledges the problem. Basically you need to dissect the butterflies and examin their genitalia. You can download that paper yourself, in PDF format, and see drawings of variously shaped male and female genitalia, here.
Therefore: There's a grouping of butterfly species known as the Checkered Skippers. That's what we'll call the one in the picture, but who knows which Checkered Skipper it is?