Letters to the Editor 19763 Share this:EmailFacebookTwitterPinterestPocketRedditPrint By Science News November 29, 2006 at 10:47 am If membership in a species is characterized by the inability to breed with members of another species, how can there be “animal species known to have arisen from crossbreeding with other species? Jeffry D. MuellerEldersburg, Md. Exceptions happen. Also, biologists argue about what defines a species. —S. Milius I suggest that the new species be named Lycaeides lolita , in honor of Vladimir Nabokov. Joseph SingerFairfax, Va.