Which of the following statements about Periplaneta is incorrect?
Males bear a pair of anal styles which are absent in females.
The haemolymph is composed of colourless plasma and coloured haemocytes.
A network of tracheae transports the atmospheric air directly to the tissues.
The gizzard helps in grinding the food particles.
The haemolymph is composed of colourless plasma and colourless haemocytes. Respiratory pigment is absent in insects.