Explanation Butterflies bring about pollination as they move from flower to flower in search of nectar. The larva of butterfly is injurious to crops as they feed on leaves. Citrus butterfly Citrus butterfly is a large attractive butterfly. It is generally found on the citrus plants particularly on orange plants. It is also referred to as the lemon butterfly. Life history of a Citrus butterfly The citrus butterfly exhibits complete metamorphosis and completes its life history in four stages- egg, larva, pupa and adult. Adult The body of an adult butterfly is composed of three regions. They are the head, thorax and abdomen.The head has a pair of antennae, which are club shaped. It has a pair of large bulging compound eyes. The mouthparts are made of a tubular proboscis for sucking nectar. When not in use, it is coiled up like a spring. The butterfly straightens its proboscis by forcing blood into it. The thorax is made up of 3 segments. It is covered with tiny hairs and every segment has one pair of jointed legs. There are 2 pairs of wings present in the thoracic segments. The forewing is present on the middle segment. The hindwing is present on the hind thoracic segment. The wings are brightly coloured - dark brown with yellow patches. Each hindwing carries 2 bright spots. The abdomen is slender and is covered by thick hair. The anus is present on the last segment. Egg The female butterfly lays eggs on the young leaves and shoots after the process of mating. Each egg is small and somewhat conical. Eggs are usually laid on the undersurface, so they are protected from direct sunlight.Eggs are scattered singly and yellowish - white in colour. The eggs are glued to the surface of a leaf by the cementing substance, to prevent them from being blown off by wind or washed away by rain water. Larva The egg hatches into caterpillars in about 2 days. The caterpillar is the larval stage and feeds on Citrus leaves. The newly hatched caterpillar is about 2 mm in length. The larva undergoes about four moultings. The larva that emerges is larger than the previous one, with every moulting. Initially the caterpillar is dark brown and later it develops irregular whitish markings. The whitish markings protect the larva against birds, which do not eat it thinking it to be their own excreta. A fully-grown caterpillar is green in colour, which camouflages it in its natural habitat. The colour of the caterpillar blends with the colour of the leaves. A fully grown larva is about 4 –5 cm long and 0.7 cm thick. The caterpillar is a segmented worm and the body is composed of three regions- head, thorax and abdomen. The head has 6 small eyes or ocelli, a pair of very short jointed antenna, well developed mouth parts with powerful mandibles to help in biting and chewing solid food. The thorax is made of 3 segments and each carry a pair of walking legs. The abdomen is divided into 10 segments. A pair of prolegs is present on segments 3 to 6. Prolegs are short and cushiony projections that help in locomotion. Prolegs are contractile in nature; their sole have minute hooks for gripping the substratum while crawling. The last segment bears a pair of prolegs called claspers. One pair of spiracles, for the purpose of breathing, is present on each of the first 8 abdominal segments. Pupa The larval stage lasts for about 3 weeks. The larva then stops feeding, becomes inactive and transforms into a pupa. The Pupa is the resting phase. It spins a small pad of silk at suitable place, usually on a twig and then attaches itself to it by means of the clasper. When it undergoes the last moulting, the discarded cuticle serves as a protective cover. The insect inside is called the pupa or chrysalis. During the pupal stage, which lasts about 10 days, most of the larval organs undergo reorganization. The changes seen include the biting mandibles being replaced by long sucking proboscis, the prolegs are lost, the short thoracic legs are replaced by longer ones and the development of wings. At the end of the pupal period, the protective covering splits and the butterfly comes out. The wings are soft and wrinkled in the newly emerged butterfly. It soon becomes hard and flat and aids the butterfly to fly off. It takes about two-and-a-half weeks to four-and-a-half months for the Citrus butterfly to complete one generation.