Morphological variation in resting-egg pattern is examined in 43 populations of Chirocephalus diaphanus carinatus from the Balkan area and is discussed in relation to geographic location. In spite of a great variation in male and female key-characters, even at the individual level, distinct and apparently constant resting-egg patterns was revealed for each population, irrespective of distribution. Such a contrasting situation stresses the need for further research at genetic or molecular level in order to ascertain the validity of the subspecies ranking, previously put into question by Belk and Brtek.