The first-instar larvae of Delia radicum (L.) and Delia antiqua (Meigen) enter host plants to feed in galleries. These galleries can be filled by a liquid resulting from the putrefaction of the host. In this study, we show that D. radicum and D. antiqua larvae have a metapneustic respiratory system in the first instar and an amphipneustic respiratory system in the second instar, as observed in the majority of cyclorrhaphous Diptera. In addition, we observed four spatulate, ramified structures on the postabdominal spiracles in all three larval instars. We propose that these structures facilitate gas exchange (CO2 and O-2), especially in the first-instar larvae when they feed in liquid-filled galleries