OT: Parasha question

A bit off topic...

This has been bugging me today so I was wondering if anyone had a good answer.

In next week's parasha (Bamidbar/Numbers 13:1), the list of the meraglim includes:

ד  וְאֵלֶּה, שְׁמוֹתָם:  לְמַטֵּה רְאוּבֵן, שַׁמּוּעַ בֶּן-זַכּוּר.	4 And these were their names: of the tribe of Reuben, Shammua the son of Zaccur.
ח  לְמַטֵּה אֶפְרָיִם, הוֹשֵׁעַ בִּן-נוּן.	8 Of the tribe of Ephraim, Hoshea the son of Nun.
יא  לְמַטֵּה יוֹסֵף, לְמַטֵּה מְנַשֶּׁה--גַּדִּי, בֶּן-סוּסִי.	11 Of the tribe of Joseph, namely, of the tribe of Manasseh, Gaddi the son of Susi.

Why wasn't mateh (tribe of) Ephraim placed under mateh Yosef (Joseph)? And why was there a separation of 2 verses between them?

I didn't see any answers in the meforshim I had available. It seems fairly glaring so I figured someone must have commented on it, perhaps in the context of the entire order listed.

Any ideas?