The morphological ontogeny of Eubelba danubedeltaica sp. nov. is described and illustrated. The adult of E. danubedeltaica is most similar to E. sculpta (Mihelčič, 1957) which differs from E. danubedeltaica by the presence of tubercle E2p, slightly longer seta c₁ and leg IV, and thicker and clearly barbed epimeral, genital, aggenital and anal setae whereas in E. danubedeltaica tubercle E2p is absent and these setae are thinner and most are smooth, except for finely barbed genital and anal setae that are clearly visible at a high SEM magnification. In the juveniles of E. danubedeltaica, most prodorsal setae are of medium size, except for short seta in in the nymphs and very long setiform bothridial seta which are strongly curved in the distal part. Most gastronotal setae of juveniles are long, or very long, except for medium-sized c₃, la, lm and h₂, and short h₃ in the larva, and medium-sized c₃ and p₂ in nymphs. The nymphs are quadrideficient and eupheredermous, i.e. they have lost the d-series setae and carry the exuvial scalps of previous instars using a cornicle located between setal pair h₃. In all juveniles, the famulus ε on tarsus I is sunken but is emergent in the adult. Seta d accompanies solenidion σ on genua I–III and φ on tibiae II–IV.