, ▁though ▁many ▁lar val ▁insect s ▁( e . g ., ▁c ater p ill ars ) ▁have ▁some ▁form ▁of ▁append ages , ▁such ▁as ▁pro leg s ▁or , ▁in ▁aqu atic ▁insect s , ▁g ills . ▁ ▁In ▁ap oc rit an ▁H ymen optera ▁( was ps , ▁be es ▁and ▁an ts ), ▁the ▁met as oma ▁consists ▁of ▁the ▁second ▁ab dom inal ▁segment ▁( which ▁typically ▁forms ▁a ▁pet io le ) ▁and ▁those ▁segments ▁posterior ▁to ▁it , ▁and ▁is ▁often ▁called ▁the ▁g aster ▁rather ▁than ▁referring ▁to ▁it ▁as ▁the ▁" ab d omen "; ▁in ▁these ▁insect s , ▁the ▁first ▁ab dom inal ▁segment ▁is ▁called ▁the ▁prop ode um ▁and ▁is ▁f used ▁to ▁the ▁thor ax . ▁The ▁met as oma ▁is ▁arm oured ▁with ▁ch it in ous ▁pl ates ▁on ▁the ▁upper ▁surface ▁by ▁the ▁ter g ites ▁and ▁on ▁the ▁lower ▁surface ▁by ▁the ▁stern ites . ▁ ▁In ▁sc orp ions , ▁the ▁met as oma ▁is ▁the ▁tail . ▁In ▁other ▁ch el ic er ates , ▁such ▁as ▁sp iders , ▁the ▁mes os oma ▁is ▁f used ▁with ▁the ▁met as oma ▁to ▁form ▁the ▁op is th os oma . ▁ ▁References ▁ ▁Category : Ar th rop od ▁an atom y <0x0A> </s> ▁Ter pin , ▁used ▁as ▁the ▁hyd rate ▁( ter pin · H 2 O ), ▁is ▁an ▁expect or ant , ▁used ▁to ▁lo