The transcriptional mbl reporter is expressed in third instar larval photoreceptors. In the brain, expression is observed mainly in post-mitotic neurons with some expression in glial cells. An intersectional strategy was used to label single cells. mbl reporter is observed in L1, L4, R7 and R8 neurons. It is detected early in pupal development but not later. mbl is expressed in a cell-specific manner that correlates with the expression of Dscam2 exon 10B but not 10A. It is not detected in mushroom body neurons that express Dscam2 exon 10A in adults.