or sulfur butterfly Any of several species of butterflies (family Pieridae) that are found worldwide. Adults have a wingspan of 1.5-2.5 in. (35-60 mm). The colour and pattern of many species vary seasonally and between sexes, but they are generally bright yellow or orange. Some have two colour patterns; for example, Colias eurytheme is usually orange with black wing margins, but some females are white with black margins. Pupae are attached to a twig by a posterior spine and a girdle of silk. The larvae feed on clover and may seriously damage crops