Notes on distinguishing the cocoons and the juveniles of hirudo medicinalis and haemopis sanguisuga (hirudinea)

Difficulties encountered previously in separating the cocoons and some juveniles of Hirudo medicinalis and Haemopis sanguisuga have been resolved by the present study. The cocoons of Hirudo medicinalis are larger and have a different structure from those of Haemopis sanguisuga. Some of the darker juveniles of Haemopis sanguisuga may be confused with those of Hirudo medicinalis, but can be separated by careful examination of both dorsal and ventral colour patterns.