none For egg deposition Alloxysta fuscicornis mounts the back of the aphid, inserts her ovipositor through the aphid cuticula and deposits the tailed egg within 2' to 6' into the 1-st to 4-th instar and also into embryonic egg of D. rapae. The Alloxysta egg loses its chorion during 24-48 h; instead a trophamnion has been developed, which after hatching, dissociates in 50 to 80 cells, which are consumed by the L1 in addition to host haemolymph. During the development in the host, larvae of all 5 instars produce a secretion by hypertrophic proctodaeum cells and secrete it into the host (that is the larva of D. rapae). This secretion might assist in the blockade of cellular host-defense. The full-grown larva of Alloxysta leaves the emptied larva of D. rapae and pupates. Hatching of the adult may occur in any position of the mumified aphid. The female Alloxysta is not able to discriminate between parasitized and non parasitized aphid. Thus, superparasitism has been often observed. The larval rivals are killed mechanically by mandible bite. Autohyperparasitism has been observed in some cases. The life span of both sexes of A. fuscicornis in the laboratory takes at least 20 days.