The Italian woman and so, therefore, also the descending woman from Italian citizen emigrated abroad, gives the citizenship to her own sons only after the entry in force of Italian Constitution and that is from 1-1-1948. 

Only in recent times relatively, after the sentence of Court of Cassation (Corte di Cassazione) n°4466/2009 has been estabilished the principle wherefore: “the effects of an unfair law in the relationship of parentage (filiazione) and marriage (coniugio) persist in the time and cannot be considered “exhausted” to the time of entry in force of Constitution (so-called persisting effect). And therefore:

The right to the Italian citizenship may be recognized even to those who were born from woman, descending from Italian ancestor emigrated abroad before 1/1/1948 BUT ONLY IN A JUDICIAL COURT.

That means who is born by Italian mother, before 1948, can’t obtain the recognition of Italian citizenship jure sanguinis with request at Consulate or at Register Office:

To have to turn to the Civil Court of Rome

-For this purpose is necessary a lawyer’s assistance;

-It is not necessary to travel in Italy in any phase of process;

-It is enough to send a proxy for the legal representation and the original documents attesting the Italian descent, translated and legalized;

-The process may be made together to other members of own family with the same descent.