It belongs to an adult female fruit fly (Drosophila melanogaster ... The only other map that comes close is a 3D diagram of the adult fly 'hemibrain', but it includes only around 20,000 neurons.

More than 40 Drosophila melanogaster genes have been discovered for which recessive, loss-of-function mutations cause adult onset degeneration of the central nervous system (CNS). A table ...