The Z line of the flight muscle of honey-bee.

The size and arrangement of the hexagonal filament lattice in the Z line of the flight muscle of honey-bee is similar to the size and arrangement of the lattice of A filaments. Z filaments show a "tubular" structure and possess a seemingly empty inner core just like A filaments do. The Z filaments are connected with a thick network transversally. The I filaments are probably embedded in this transversal network on both sides of the Z line; they cannot be recognized inside the Z line. The filament lattice of the Z line does not exclude the possibility of the A filaments to be connected to the Z line through the connecting filaments, or continuously to pass from one sarcomer into the other.