The four ventral-longitudinal muscles (VL1-4) generally have a rounded morphology and fail to connect to any tendon cell in the abdominal segments of kon^C41/kon^C452 embryos.

Muscle VL1 exhibits a rounded morphology in approximately 80% of cases in kon^C452, kon^C452/kon^C25, kon^C452/kon^C1139 and kon^C452/Df(2L)TW137 embryos. In most of the remaining cases, the VL1 muscle fails to span the entire abdominal segment.

The VL1 muscle founder cell is seen at its normal posterior location in kon^C452/kon^C1139 embryos at the appropriate stage. VL1 also polarises normally and the anterior end begins its directed migration in the mutant embryos. However, during this anterior migration, defects are seen; the VL1 muscle appears to terminate prematurely compared to wild type and although filopodial extensions of the VL1 muscle do often reach the anterior segment border, they apparently fail to recognise their attachment sites, as no connection is established. The unattached myotubes continue to project filopodia in all directions, but no longer sustain a directed migration towards their target.