About Eurema smilax (Donovan, 1805)
Adults of Eurema smilax have a wingspan of 30–34 mm, with females slightly larger than males. They are yellow with black tips on the upper surface of the forewings, and their colouration varies depending on flight period. In southern Australia, summer-flying forms are typically pale yellow, with few or no brown markings on the undersides of the wings. Winter forms are brighter yellow, with distinct brown markings on the wing undersides. Males are generally a brighter yellow than females. The eggs are initially white, turning yellowish as they develop. They are spindle-shaped, around 1.2 mm tall, and laid singly on a host plant. In spring, eggs hatch after approximately 7–11 days. Newly hatched caterpillars are pale yellow, and quickly become greenish. Third and fourth instars develop a darker dorsal line and a yellow lateral line. Mature larvae measure 18–22 mm in length. All larval stages have specialized poison-secreting hairs, with poison visible as clear droplets at the ends of the hairs. Pupae are green, approximately 15 mm long, and attached to the host plant by a cremaster and a central silken girdle. The head of the pupa may point either upwards or downwards. The pupal stage lasts around 8–13 days. This butterfly occurs across all of mainland Australia, with occasional records from Kangaroo Island, Lord Howe Island and Tasmania. It has also been recorded in India, Java and Niger. Recorded larval host plants for E. smilax are Senna acclinis, Senna coronilloides, Senna gaudichaudii, Senna artemisioides, Senna odorata, Senna petiolaris, Senna surattensis, Senna alata, Senna auriculata, Cassia fistula, Neptunia gracilis, Neptunia monosperma, and Paraserianthes lophantha.
