The nervous system of Drosophila embryos or larvae

Left: Top view onto a maggot of Drosophila; red box indicates the position of the selection shown on the right side. Right: Details of the nervous system; Interneurons (IN) and efferent neurons (EN) lie in the cell body layer of the CNS (cortex, CX), sensory neurons (SN) in the periphery. All send processes towards the synaptic neuropile (NP). Efferent motorneurons project through segmental nerves (N) towards muscles (M) where they form neuromuscular junctions (NMJ). Black arrows indicate anterior.

Source: picture modified from Landgraf, M., Sánchez-Soriano, N., Technau, G. M., Urban, J. & Prokop, A. Charting the Drosophila neuropile: a strategy for the standardised characterisation of genetically amenable neurites. Dev. Biol. 260, 207-225 (2003).