In
Rhodnius
most of the haemoglobin ingested is broken down in the lumen of the gut to protohaematin which is excreted unchanged. But a small amount is absorbed and circulates in the haemolymph as kathaemoglobin (parahaematin). This is taken up by the salivary glands where it appears as a cherry-red pigment with properties similar to haemalbumin. Blood pigment is also transferred to the yolk of the eggs and becomes concentrated in the stomach of the newly hatched nymph as a bright red fluid (parahaematin). In the next few days most of this is digested in the gut to give protohaematin; some is transferred to the salivary glands to give rise to their usual pigment.
