Problem in brood box

[ConfedMarine]

While checking my brood box before placing Apistan strips, I found and removed (a few are still in their cells) 3 bee pupa. They are approximitly at the 15-18 day stage. The heads are missing, "sliced" at an angle from top to bottom toward the abdomen. It is such a clean angle that is why I describe it as a "cut". There is no odor or discoloration. The cells were not capped and the pupa slide back and forth in the cell. The cell pattern on the frames are normal. This problem is only on one side of one frame.Thanks in advance for any input.

[Michael Bush]

My guess is there is a dearth and they don't want more mouths to feed.