IMMATURE INSECTS – TIPS TO IDENTIFYING LARVAL STAGES OF SELECTED ORDERS
Immature stages of Coleoptera (Beetles) are called “Grubs”. The usually do not have not prolegs (leg like structures). Grubs may be “C” shaped with hard head capsules (weevils, scarab beetles) or may have true legs protruding out from body with reduced head capsule and forward facing mouthparts (Flea Beetles, Lady Beetles)
Immature stages of Diptera (Flies, Mosquitos) are called “Maggots”. They usually do not have prolegs. Head capsule and mouthparts vary widely, usually look like two “Rods” that operate in a pair for beneficials such as syrphid flies. Other mouthparts resemble sponges or even highly developed filters. Some maggots have terminal appendages that look like tubes sticking out from their abdominal segments.
Immature stages of Lepidoptera (Butterflies, Moths) are called “Caterpillars” They have 3-5 pairs of prolegs with small hooks called “CROCHETS” that resemble knitting needles. They have a hard head capsule with chewing mouthparts.
The immature stages of Hymenoptera (Bees, Sawflies) have specific term for the larvae. They have 6-9 pairs of prolegs with NO CROCHETS. Head capsule varies – Most plant feeding hymenoptera larvae have a hard head capsule and chewing mouthparts.
Immature stages of Neuroptera (Lacewings) have no specific term for the larvae. They have no prolegs but have true legs protruding out from body. They have a reduced head capsule and forward facing mouthparts that resemble two large
hooks.
All immature insects are always referred to as “Nymphs” if they undergo incomplete metamorphosis or “Larva(e)” if they undergo complete metamorphosis. Only larvae of certain orders that undergo complete metamorphosis are listed here.
An “Instar” is period between molts that an immature insect undergoes.
Information from Casey Sclar, Plant Health Care Division Leader, Longwood Gardens
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