Larva & Pupa

TYPES OF LARVAE

            Larva is the second immature stage of insects, which is the active stage. It is the stage between egg and pupal stages in insects with complete metamorphosis. Larvae totally differ from the adults.

Types of larvae

Larval type	Description (Example)
Protopod	Resembles immature embryo, abdominal segmentation absent, thoracic and cephalic appendages rudimentary (Early instars of endoparasitic hymenoptera)
Oligopod	Thoracic legs only
Campodeiform	Body flattened with a typical prognathous head well developed thoracic legs (ladybird beetle, aphidlions and antlions)
Scarabaeiform	Stout semi cylindrical, C-shaped fleshy body, legs shorter (Coconut Rhinoceros beetle grub)
Elateriform	Flat, linear, long, resemble a rusted wire (click beetle)
Polypod / eruciform	Thoracic legs well developed, five paries of prolegs, one pair each on abdominal segments 3-6 and 10 (clasper) (Caterpillars)
Hairy	Sparase, dense, or tufts of irritating hairs all over the body (groundnut red hairy caterpillars)
Spiny	Spine like out growths on the body (Castor spiny caterpillar)
Slug	Short, robust, fleshy,  thoracic legs minute, head small, retractile, prolegs absent, poisonous spines (scoli) all over the body (Castor slug caterpillar)
Semilooper	Prolegs on segments 3 and 4 either absent or vestigial, larva forms a semi loop when moving (castor semilooper)
Looper	Prolegs in segments 6 and 10 only, larva forms a complete loop, stick like (Daincha looper)
Apodous	Leg less, with or without head capsule
Acephalous	Head absent, mouth hooks (Housefly maggot)
Hemicephalous	Head capsule reduced, can be withdrawn into thorax(horsefly, robber fly, tipulid flies)
Eucephalous	Head capsule well developed (Mosquito larva, red palm weevil grub)

TYPES OF PUPA

            Pupa is the resting stage in all holometabolan insects. During this stage the larval characters are destroyed and adult features are created wherein the gonads mature, mouthparts, the digestive system reorganized and wings develop. Based on the nature of attachment of appaendages, insect pupae are classified into three main types.

Types of pupae

Pupal type	Description
Obtect	Antenna, wing pads, legs and other appendages fused to the body, many obtect pupae often protected by cocoon constructed using various materials (moths) Silken cocoon(silk) - Silkworm Earthen cocoon (soil + saliva) – Gram pod borer Hairy cocoon (body hair) – Woolly bear Frassy cocoon (frass + saliva) – Coconut black headed caterpillar Fibrous cocoon (fibres) – Coconut red palm weevil Leafy cocoon (leaf + silk fibres) – Leaf folder
Chrysalis	Angular, attached to the substratum by a hook like structure at the end of the abdomen (cremaster) and by two silken threads over the midregion of the body (Girdle) (butterflies)
Tumbler	Comma shaped with rudimentary appendages, breathing trumpets in the cephalic region, anal paddles at the abdominal end (Mosquito)
Exarate	Antenna, wing pads, legs and other appendages free, not glued to the body (Beetles, bees)
Coarctate	Larval skin (exuviae) hardens, barrel-like, air and water proof case (puparium), covers the pupa (True files)

 

            Alternatively, based on the articulation and development of mandibles, pupae may be adecticous and decticous. In adecticous pupae, the mandibles are often reduced and not articulated whereas in decticous type, the mandibles are well developed and often articulated.