C&A:

The clarinet plays the melody on the first chorus;  the second chorus (32 bars just before the guitar solo) is split evenly between vibes and piano;  after the eight-bar guitar solo, the clarinet melody closes out the take in eight measures.

Except for the modified melody line on the pickup bar, this studio Poor Butterfly 8-bar solo is fairly standard Charlie Christian. An excellent solo…until you compare it to the stunning one on the live version three weeks later in the month.  There’s a few blue notes tossed in—unexpectedly in the second measure (bent b9).  The F9 figure on the last bar is the same (with identical notes) as the one that ends his On the Alamo 8-bar solo over an Ebmaj nine months earlier.  In fact, his solo here, although in a different key and taken at a quicker tempo, reminds me of the way he constructed his solo on Alamo.