The Castor Semi-Looper, Achaea janata, is a Noctuidmoth, the caterpillars of which are termed 'semi-loopers' due to their mode of locomotion and feed on Castor Ricinus communis and both Brassica and Ficus species. As they feed off the Castor Oil plant exclusively they are extremely poisonous and should be avoided at all costs.
It is found from the Indo-Australian tropics and subtropics, extending south to New Zealand and east through the Pacific archipelagoes to Easter Island.
The caterpillars are black in colour with white head and have a red knob on a tail. In the last stages the body turns brown or bluish-grey and the tail becomes black as well with the belly and the legs becoming orange.