In the 1940s, a decade before achieving international renown with “Lolita,” Vladimir Nabokov solidified his reputation as a lepidopterist by reclassifying the wide-ranging North American butterfly genus Lycaeides, the “blues.”

Nabokov divided the blues into two large species — Lycaeides melissa, the Melissa blue, and Lycaeides idas, the northern blue, with overlapping ranges in the mountains of the West. He also theorized that the blues he found high in the Tetons and Colorado Rockies were hybrids, but he lacked the tools to prove it.

Now, a group of scientists from Texas State University, the University of California at Davis, the University of Nevada at Reno and the University of Tennessee have proposed that an “unnamed” population of Alpine Lycaeides in the Sierra Nevada is a hybrid species formed through an ancient mixing of Lycaeides melissa and Lycaeides idas.

These blues have colonized the treeless alpine region, at a higher altitude than the habitats of their parents, said Zachariah Gompert, a graduate student in biology at Texas State and principal author of the group’s paper, published in the Nov. 30 online edition of Science. Lycaeides melissa is found in the Great Basin on the east side of the Sierras; Lycaeides idas frequents wet meadows that reach halfway up the west slope.