ckn^L.Q34stop homozygous or ckn^L.Q34stop/Df(2R)BSC330 mutant embryos display consistent motor axon projection defects, exhibiting classic ISNb 'bypass' phenotypes, where ISNb axons fail to innervate the ventrolateral muscle field. These axons appear to defasciculate normally from the primary ISN branch at the exit junction, but fail to enter the ventral muscle field, instead bypassing their targets as they extend parallel to the primary ISN fascicle. Frequently, mis-targeted ISNb axons reach back from the dorsal edge of muscle 12 to innervate the ventrolateral muscle field. In the majority of affected nerves, ISNb axons are visible as a distinct fascicle next to the ISN.