Lepidopterology is the study of butterflies and moths. If you plan to study lepidopterology, you might go to college and major in zoology or biology.
People who study insects call their specialty entomology, and when an entomologist focuses specifically on insects with scaly wings that hatch from caterpillars, she calls her field lepidopterology. One of the most famous amateur lepidopterology enthusiasts was the writer Vladimir Nabokov, who collected butterfly specimens throughout his life. The word itself comes from the Greek roots lepido, "scale," and pteron, "wing or feather."