dˈuː tə ðə wˈaɪdspɹɛd kˌʌltɪvˈeɪʃən ʌvðɪ ælfˈælfə, ðə hˈoʊst plˈænt fɔːɹ sˈiː. jˈuːɹɪθˌiːm ænd sˈiː. fˈɪlɑːdɪs, ðə spˈiːsiːz wʌz ˈeɪbəl tʊ ɛkspˈænd ðɛɹ ɹˈeɪndʒᵻz əkɹˌɑːs mˈoʊst əv nˈɔːɹθ ɐmˈɛɹɪkə.
Due to the widespread cultivation of the alfalfa, the host plant for C. eurytheme and C. philodice, the species was able to expand their ranges across most of North America.