Hemizygous third instar larvae show gut melanisation not accompanied by tissue overgrowth or hemocyte encapsulation. A large number of heterozygous larvae also develop melanisations in the gut walls.
Hemizygous embryos hatch with normal cuticles. No transformation of anterior segments toward abdominal segment A8 is seen. These larvae are smaller than wild-type and attain the second instar with approximately a 24 hour delay. Most of the larvae die several days later without undergoing a second moult. All the major imaginal discs are smaller than in wild-type larvae. Almost all second instar larvae have melanotic pseudotumours. Areas of melanisation are seen touching the imaginal hindgut ring and hindgut. No homozygous clones are seen on individuals irradiated earlier than 48 hours before puparium formation (BPF). Only very few, tiny clones are seen on the hemi-notum of flies irradiated between 0 and 48 hours BPF, and clones are not seen on the abdomen in these flies. Does not rescue the lack of abdominal segment differentiation seen in the progeny of hb4 nosL7/nosL7 females. mxcSO/mxc22a-6 females die as pharate adults with extremely reduced eyes and head structures. Antennal segments 1 and 2 appear normal, whereas antennal segment 3, the arista and maxillary palps are reduced. Head structures derived from the labial and clypeo-labial discs, such as the proboscis, labrum and clypeus appear normal. These flies have melanotic spots.
Homozygotes die as first or second instar larvae. mxcG9/mxc22a-6 females lay many small eggs with a thin chorion and small dorsal appendages that collapse after oviposition. mxcM1/mxc22a-6 and mxcG46/mxc22a-6 females have reduced viability and do not lay eggs. Some egg chambers contain the normal number of nurse cells, but oogenesis appears arrested before stage 7-8. Egg chambers degenerate in older flies.