At the time when the Q descendants are beginning their migrations in early L1 larvae 4-4.5 hours post-hatching, Pspon-1::gfp expression was observed in posterior body wall muscles cells, but not in the Q cells as determined by the Q-cell specific marker rdvIs1 (Pegl-17::mCherry) (Branda and Stern, 2000; Ou et al., 2010). Pspon- 1::gfp expression was in body wall muscle cells adjacent to the Q neuroblasts, with expression extending posteriorly to the tail, but only a short distance anteriorly.