What is the earliest known reference to a Torah portion by name?

Question

What is the earliest known reference to one of the 54 Torah portions by name? (Is it ever done in the Talmud, for instance?)

For reference, the 54 Torah portions are:

Bereshit Noach Lech Lecha Vayera Chayye Sarah Toldot Vayetze Vayishlach Vayeshev Miketz Vayigash Vayechi

Shemot Va'era Bo Beshallach Yitro Mishpatim Terumah Tetzaveh Ki Tisa Vayakhel Pekudei

Vayikra Tzav Shemini Tazria Metzora Acharei Mot Kedoshim Emor Behar Bechukkotai

Bamidbar Naso Behaalotecha Shlach Lecha Korach Chukat Balak Pinchas Matot Massei

Devarim Va'etchanan Ekev Re'eh Shoftim Ki Tetze Ki Tavo Nitzavim Vayelech Haazinu V'Zot HaBerachah

Answer 1

See Megillah 30a for a reference to 2 specific parshiot - Ve'ata Tetzaveh and Ki Tissa.

The names of the parshiot frequently aren't exactly the same as we currently call them. But, clearly, the names of at least some of the parshiot were known at the time of the Talmud Bavli.

Bavli doesn't mention too many parsha names because there are very few rules regarding when specific parshiot need to be read. The page I linked to, seems to be one of the few references to having specific parshiot read by a specific time of the year.

Answer 2

An argument could be made that it's Parshat אַחֲרֵי מוֹת mentioned in the Mishna in Megila 3:5 which states:

בְּפֶסַח קוֹרִין בְּפָרָשַׁת מוֹעֲדוֹת שֶׁל תּוֹרַת כֹּהֲנִים (ויקרא כב). בַּעֲצֶרֶת, שִׁבְעָה שָׁבֻעוֹת (דברים טז). בְּרֹאשׁ הַשָּׁנָה, בַּחֹדֶשׁ הַשְּׁבִיעִי בְּאֶחָד לַחֹדֶשׁ (ויקרא כג). בְּיוֹם הַכִּפּוּרִים, אַחֲרֵי מוֹת (שם טז). בְּיוֹם טוֹב הָרִאשׁוֹן שֶׁל חָג קוֹרִין בְּפָרָשַׁת מוֹעֲדוֹת שֶׁבְּתוֹרַת כֹּהֲנִים (ויקרא כג), וּבִשְׁאָר כָּל יְמוֹת הֶחָג בְּקָרְבְּנוֹת הֶחָג (במדבר כט):‏

On [the first day of] Passover, the section in Leviticus relative to the festival must be read; on the feast of weeks, that commencing, "Seven weeks shall you count," (Deut. 16); on the feast of new year, the section commencing, "In the seventh month, on the first day of the month" (Num. 29:1); on the day of atonement, that of ‏ Acharei Mot (Lev. 16); on the first day of the feast of tabernacles, the section in Leviticus relative to the festivals must be read (Lev. 23) and on the other days of that festival, the offerings for each day (Num. 29:17).