On page 41 of Rouse’s First Greek Course there is this.
τὸ λεγόμενον τοῦτ’ ὅμοιον ἐστί νῦν· τἄνω κάτω, τὰ κάτω δ’ ἄνω.
The best I can come up with is this (it is a stand alone sentence so there is no context to help).
This spoken thing is the same now; the things above are downwards and the things below above.
I’ll take a stab at it, “This saying is now common: what is up is down and what is down is up.”
Are you sure ὅμοιον is in the text? I don’t see it here:
https://archive.org/stream/FirstGreekCourse/RouseGreekCourseResized#page/n49/mode/2up
And the accentuation seems wrong if it’s there. It’s in the next sentence, however.
I split that PDF and rotated it a while back, so this may be an easier link to use:
https://archive.org/stream/FirstGreekCourse/RouseGreekCourseResized#page/n49/mode/2up
Yes I slipped up and copied it in from the next sentence. 
So it should be:
τὸ λεγόμενον τοῦτ’ ἐστὶ νῦν· τἄνω κάτω, τὰ κάτω δ’ ἄνω.
If I follow Pros suggestion that would give:
This saying is now : what is up is down and what is down is up.
Perhaps νῦν means something like “current”?
I just can’t see why anyone should say such a thing.
I just can’t see why anyone should say such a thing
.
I can’t either. And the next sentence after the one you asked about is even more bizarre.
Some latitude has to be given to textbook writers who have to construct sentences for translation with limited vocabulary and syntax. Dickey seems to take delight in concocting ridiculous sentences for translation into Greek.
“The prostitute’s beauty enslaved my son before her lies caused him to revolt.”
“If only that old woman were not encouraging the enemy to set up a trophy!”
“Your wife is conscious of having promised to swim through the river.”
“A prudent young man would be learning many arts privately during the winter, too. This man, although he is well spoken of, is not prudent.”
Isn’t “τὸ λεγόμενον” the same as the proverb or the saying? So then you get something like “this proverb is (fitting) now: What’s above is below and what’s below is above.” I can think of contexts for saying something like that.
This is very illuminating! He we are, witnessing the age-old phenomenon of textual corruption! 
it seems like some kind of a garbled reference to Heraclitus fr.60, which it is given by Hippolytus in two forms:
καὶ τὸ ἄνω καὶ τὸ κάτω ἕν ἐστι καὶ τὸ αὐτό
ὁδὸς ἄνω κάτω μία καὶ ὡυτή
the second supposedly being the actual quote, with the Ionic “ὡυτή”
He we are, witnessing the age-old phenomenon of textual corruption!
Self-referential?
Ahh Heraclitus! The philosopher who said you can never go into the same river twice. The sort of thing that is obviously wrong until someone explains why it is obviously correct. No wonder it made no sense to me - Thanks.
What I should have said is Hylander is following an alternative manuscript tradition that arose because a pedantic scribe corrected the original 
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τἄνω κάτω, τὰ κάτω δ’ ἄνω seems relatively transparent, but τὸ λεγόμενον τοῦτ’ ἐστί νῦν seems like the sort of expression that is inscrutable outside some context. “This is what is being said right now”? Maybe someone has a better idea about this, but it strikes me that this is not a helpful way to teach Greek.
From the scholia to In Theaetetum (where I think it will be more understandable):
παροιμία, ἄνω κάτω πάντα, ἐπὶ τῶν τὴν τάξιν μεταστρεφόντων. Μένανδρος Ἐγχειριδίῳ,
καὶ ἐν Χήρᾳ τὸ λεγόμενον τοῦτ’ ἐστὶ νῦν,
τἆνω κάτω, φασί, τὰ κάτω δ’ ἄνω
Perhaps Rouse has simply removed the first three words to make it more universally applicable. But notice how the scholion is printed in this 1839 edition:
https://books.google.com/books?id=UyNUAAAAcAAJ&pg=PA897&lpg=PA897
I think that it’s possible that Rouse missed the start of the first line due to the printing. As much as I love Rouse, there are a number of places in First Greek Course (see On the Murder of Eratosthenes), in his Lucian (see his Judgment of Paris minus the nudity), etc., where his selections are harder to read than the original because of missing information. Not a problem for his classroom use, I imagine, but it can sometimes make it difficult for self-study.
I’m wrong and Rouse is correct. Χήρᾳ is the play, not a place.
καὶ ἐν Χήρᾳ just means “in his play Chera.” [Note: Originally cross-posted with Jeidsath]. It would be unmetrical if it were part of the trimeter, and “Chera” (“The Widow”) is a known play by Menander. So we’re left with Rouse’s quotation of an out-of-context Greek sentence: τὸ λεγόμενον τοῦτ’ ἐστί νῦν· τἄνω κάτω, τὰ κάτω δ’ ἄνω.
“This is what is being said now [?]: everything is upside down.”
I don’t think there’s any reason to think this necessarily has anything to do with Heraclitus. The Scholiast just says it’s a proverbial expression (παροιμια). It sounds like it might be a description of a situation in a comedy.
It’s not even clear where the scholiast’s words end and where those of Menander begin. Shouldn’t it be punctuated like this:
Μένανδρος Ἐγχειριδίῳ, καὶ ἐν Χήρᾳ τὸ λεγόμενον τοῦτ’ ἐστί· “νῦν τἄνω κάτω, φασί, τὰ κάτω δ’ ἄνω”
τἄνω κάτω, φασί, τὰ κάτω δ’ ἄνω isn’t even a complete trimeter.
I think that the νὖν contrasts with λεγόμενον. “The saying is fresh” or that sort of thing.
“νῦν τἄνω κάτω, φασί, τὰ κάτω δ’ ἄνω”
Maybe I’m reading it wrong, but wouldn’t putting νῦν there make a 4th foot dactyl and a second foot spondee? And still not complete the line (missing a syllable at the start).
But if we want to go that route, here’s my try: (Taking φασι as part of the scholion)
τοῦτ’ ἐστί νῦν τἄνω κάτω τὰ κάτω δ’ ἄνω
For Menander, a 5th line anapaest is common, and a number of his lines don’t include a proper caesura,
I don’t think the words of the quote amount to a trimeter, and I wonder whether φασί is part of the quote, but it strikes me that καὶ ἐν Χήρᾳ τὸ λεγόμενον τοῦτ’ ἐστί belongs together: “in the Chera this is what is said” or “this is the expression”. The scholiast is commenting on the expression ανω κατω παντα. He says it’s a παροιμια – a proverbial expression επι των την ταξιν μεταστρεφοντων. He cites Menander Ενχειριδιωι (why dative?), “Handbook”, and then adds καὶ ἐν Χήρᾳ τὸ λεγόμενον τοῦτ’ ἐστί. But the next word, νῦν, seems to belong to what follows, not what precedes. Maybe the subject of φασί is the characters of the play, and it’s not part of the quote.
The scholiast is commenting on this from Plato’s Theatetus (153d; Socrates is speaking):
ἔτι οὖν σοι λέγω νηνεμίας τε καὶ γαλήνας καὶ ὅσα τοιαῦτα, ὅτι αἱ μὲν ἡσυχίαι σήπουσι καὶ ἀπολλύασι, τὰ δ᾽ ἕτερα σῴζει; καὶ ἐπὶ τούτοις τὸν κολοφῶνα, ἀναγκάζω προσβιβάζω τὴν χρυσῆν σειρὰν ὡς οὐδὲν ἄλλο ἢ τὸν ἥλιον Ὅμηρος λέγει, καὶ δηλοῖ ὅτι ἕως μὲν ἂν ἡ περιφορὰ ᾖ κινουμένη καὶ ὁ ἥλιος, πάντα ἔστι καὶ σῴζεται τὰ ἐν θεοῖς τε καὶ ἀνθρώποις, εἰ δὲ σταίη τοῦτο ὥσπερ δεθέν, πάντα χρήματ᾽ ἂν διαφθαρείη > καὶ γένοιτ᾽ ἂν τὸ λεγόμενον ἄνω κάτω πάντα
So Plato is referring here to τὸ λεγόμενον ἄνω κάτω πάντα, “as the saying goes [τὸ λεγόμενον], ‘everything is upside down.’” The the scholiast is giving another version of this expression from Menander’s Chera. I think this shows that καὶ ἐν Χήρᾳ τὸ λεγόμενον τοῦτ’ ἐστί belongs together, and τὸ λεγόμενον τοῦτ’ ἐστί isn’t part of the Menander quote. I’m not sure how νῦν fits in, but it seems more likely to belong with the quote.
But I think the sentence for translation in Rouse isn’t helpful for students learning Greek.
Hylander, I think that you must be right about τὸ λεγόμενον, looking at the Plato being commented on.
καὶ γένοιτ’ ἂν τὸ λεγόμενον ἄνω κάτω πάντα;
(EDIT: And now I’ve cross-posted with Hylander.)
I also notice that the scholiast is saying that there are two Menander sources for the line, the Dagger and in the Widow. Maybe we could be looking and two quotes? τἆνω κάτω and τὰ κάτω δ’ ἄνω. But they fit together too well. I think it must be one.
I do see two metrical problems with the lines as we have them. No caesura in the first. And a second syllable dactyl break in the second line. The incompleteness that you’ve mentioned bothers me less than the second syllable break in a dactyl, as Menander often breaks up his speeches near the ends of lines in Dyskolos.
τὸ λεγόμενον τοῦτ’ ἐστὶ νῦν, (3: tribrach 4: iambus 5: spondee 6: spondee)
τἆνω κάτω, φασί, τὰ κάτω δ’ ἄνω (1: spondee 2: iambus 3: dactyl 4: iambus 5: iambus)
However, look at the elision in τοῦτ’ ἐστὶ compared to other parts of the scholia, where there is none. Someone (a copyist, the editor?) thought that part of the quote was metrical.
Your point about elision is well taken.
This could be metrical–parts of two iambic trimeters, with resolution:
χ _ υ _ | τὸ λεγόμενον | τοῦτ’ ἐστὶ νῦν,
τἄνω κάτω, | φασί, τὰ κάτω | δ’ ἄνω υ x
Iambic trimeters consist of three iambic metra, which (without permissible resolution of _ to υ υ) consist of x _ υ _. Iambic trimeters shouldn’t be analyzed as iambic “feet” (υ _), but rather as metra. That’s why they’re called iambic trimeters and not iambic hexameters. Dactylic hexameters, however, can be analyzed in terms of dactylic “feet.”
Well, regardless of terminology, φασί, τὰ (_ u | u) – what I’m calling a 3rd foot dactyl broken on the second syllable – wouldn’t ever occur in tragedy. Maybe there is an exception for these syllable breaks in comedy? We’re reaching the limits of my knowledge.