A: posterior spiracular opening of first-instar larva. (Front View)

B: posterior spiracular opening of second-instar larva. (Front View)

C: posterior spiracular opening of third-instar larva. (Front View)

D: posterior spiracle third-instar larva.

E: anterior spiracle third-instar larva.

at: atrium

cst: cuticular strand, i.e., remnant of cuticular spiracle

p: spiracular papilla

sc: scar

spo: spiracular orifice

tr: trachea