n small animal aquatic 

Perception +8; low-light vision, wavesense (imprecise) 30 feet

Skills Athletics +10, Stealth +9 (+11 in water)

Str +3 Dex +2 Con +4 Int -5 Wis +1 Cha -5

AC  19; Fort +11, Ref +9, Will +6

HP 46

Speed 10 feet, swim 30 feet

Melee [>] mandibles +12 (agile), Damage 1d10+6 piercing

Extend Mandibles [>] The giant dragonfly nymph extends its jaws to a surprising distance. The dragonfly nymph makes a mandibles Strike with a reach of 10 feet, but the mandibles lose the agile trait for this Strike.

Bestiary 2, page 98.