Optic lobes from 40 wandering third instar larvae were dissected and cells were dissociated both mechanically and enzymatically.

Reads were processed using CellRanger (10x Genomics) v3.0.1. They were mapped to the Drosophila melanogaster reference genome BDGP 6.88. For quality filtering, only genes that were expressed in at least 3 cells across all cells were retained, and only cells with at least 200 genes. Dimensionality reduction and clustering were performed with Seurat v3 by computing 150 principal components and with a resolution of 2.